delivered the opinion of the court:
On June 10, 1976, the property at 5017 South Ellis Avenue, Chicago, was sold for nonpayment of taxes. A certificate of sale was issued to Phoenix Realty, which thereafter assigned the certificate to Dorothy Ware. On June 7, 1978, in anticipation of the expiration of the period of redemption, Ware filed a petition for a tax deed to the property. At the hearing on the petition on October 17, 1978, an attorney for the Chicago Park District (Park District) appeared and produced a sheriff’s deed to the property in issue. The Park District attorney alleged that the Park District had not received the requisite personal notice of the expiration of the period of redemption and that therefore Ware’s petition should be denied. The trial court denied the petition.
Ware filed a post-trial motion in which she alleged that new evidence had been discovered which would require that the court issue a tax deed to Ware. The court granted Ware a new trial at which the new evidence was presented. Despite this evidence, the trial court again denied Ware’s petition. Ware appeals from this order.
The property which is the subject of this appeal, 5017 South Ellis Avenue, Chicago, was deeded to the Illinois Protestant Children’s Home (the home) in 1947. Thereafter, the subject property was conveyed to Florence Budd and then to Flo Budd Antiques, Inc. In 1970, the Illinois Attorney General’s office sued to set aside these latter conveyances on the grounds that they were without corporate author*32ity and were for Budd’s personal benefit.
The matter came before Judge Epstein, who ordered that the subject property be conveyed back to the home. The foregoing proceedings were concluded on March 5, 1973. During these proceedings, the structure on the subject property was damaged by fire and was demolished by the city of Chicago in 1972. The city thereby acquired a demolition lien of $4,500, which it sought to foreclose in 1973.
While the demolition lien foreclosure proceedings were pending, Judge Epstein was attempting to find an organization to accept the subject property. It was impossible for the home to take the property back because it had been dissolved by decree in 1962. Judge Epstein sought to find an organization that could utilize the property for recreational use. Among those contacted was the Chicago Park District. The commissioners of the Park District elected to attempt to acquire the subject property. Accordingly, the Park District filed a petition before Judge Epstein in December 1975 asking him to utilize the cy pres doctrine to convey title to the Park District. Judge Epstein granted the Park District’s petition on January 9, 1976, and ordered that a sheriff’s deed be delivered to the Park District. For reasons which are not apparent from the record on appeal, the Park District did not seek to obtain the sheriff’s deed until October 13, 1978, over 21/2 years after Judge Epstein’s order.
On June 10, 1976, the subject property was put up for sale, pursuant to court order, for nonpayment of taxes from 1947 to 1974. The property was purchased at the tax sale by Phoenix Realty, which thereafter assigned the certificate of sale to Dorothy Ware (appellant).
On October 27, 1977, Ware filed a petition for appointment as receiver to prevent waste to the property in issue. The Park District appeared at the hearing on the petition by one of its attorneys, who rep-, resented to the court that the Park District had- “no interest whatever” in the subject property. Ware’s petition to be appointed receiver was granted.
Meanwhile, the city of Chicago’s suit to foreclose on its demolition lien led to an order authorizing a sale of the subject property to satisfy the city's lien. The sale was scheduled for November 16, 1977. On November 14, 1977, Ware tendered to the city a sum sufficient to redeem the property from the demolition lien. This tender was rejected. On the morning of November 16, 1977, Ware secured a temporary restraining order to prevent the demolition lien sale from proceeding. Nonetheless, the sale took place and the subject property was sold. Ware was later able to suspend the results of the sale, and the city thereafter accepted Ware’s payment of the demolition lien.
*33On June 7, 1978, Ware filed her petition for a tax deed in anticipation of the expiration of the two-year redemption period following a tax sale. Ware did not give personal notice of the expiration of the redemption period to the Park District. The redemption period expired on September 29, 1978, and a hearing on Ware’s petition was held on October 17, 1978. The Park District appeared at this hearing by the same attorney who had appeared at the hearing on receivership. The attorney produced a sheriff’s deed to the subject property which had been issued on October 13, 1978, pursuant to Judge Epstein’s order of January 9, 1976. The court denied Ware’s petition on the grounds that Ware had failed to give proper notice to the Park District of the expiration of the redemption period. The court ruled that the order of January 9, 1976, could not be collaterally attacked and held that the Park District attorney’s earlier statement that the Park District had no interest in the subject property was not a waiver of the Park District’s rights and did not estop the Park District from asserting its sheriff’s deed.
Ware filed a motion for a new trial. A new trial was granted on the basis of a letter indicating that the Park District had lost interest in acquiring the subject property as early as the time of the purported waiver by the Park District attorney. Despite this new evidence, the trial court again denied Ware’s petition. Ware appeals from this order.
Appellant first contends that the trial court erred in ruling that the order of January 9, 1976, could not be collaterally attacked. That order directed the sheriff of Cook County to deliver a deed to the property in issue to the Chicago Park District and it authorized the Park District to accept the deed. A sheriff’s deed was executed on October 13, 1978. The Park District produced this deed at the hearing on the instant petition for a tax deed and it was this deed which established the Park District’s right to receive personal notice of the expiration of the redemption period. Appellant’s failure to give the Park District personal notice of the expiration of the redemption period was the basis for the denial of appellant’s petition. On appeal, appellant contends that the order of January 9, 1976, was void and did not, therefore, convey a property interest to the Park District sufficient to entitle them to personal notice of the expiration of the redemption period.
A judgment may be collaterally attacked only when the court which rendered the judgment lacked jurisdiction over the parties and subject matter (Johnston v. City of Bloomington (1979), 77 Ill. 2d 108, 112, 395 N.E.2d 549) or lacked the inherent power to enter the order involved (City of Chicago v. Illinois Fair Employment Practices Com. *34(1975), 34 Ill. App. 3d 114, 117, 339 N.E.2d 260). Collateral attack on judgments is not permitted for nonjurisdictional errors or irregularities. (See Federal Sign & Signal Corp. v. Czubak (1978), 57 Ill. App. 3d 176, 179, 372 N.E.2d 965.) In the instant case, it is not disputed that the court which rendered the order of January 9, 1976, had jurisdiction of the parties and subject matter involved. The essence of appellant’s contention is that the circumstances in that case did not warrant the court’s use of the cy pres doctrine to direct a conveyance to the Park District. Even assuming that appellant is correct, a wrongful application of the cy pres doctrine does not constitute a jurisdictional defect such as to warrant a collateral attack on the order of January 9, 1976. The court did not lack the power to utilize the cy pres doctrine because it is a court hearing chancery matters in which the doctrine may properly be utilized. (See 8 Ill. L. & Prac. Charities secs. 42, 43, at 57-59, (1954).) Appellant merely contends that the court wrongly applied the doctrine under the circumstances presented. The power of a court to decide includes the power to decide erroneously, and any erroneous decision so made is binding as a court decision until set aside or corrected on appeal. (Baker v. Brown (1939), 372 Ill. 336, 343, 23 N.E.2d 710.) Because appellant does not point to a jurisdictional defect in the judgment of January 9, 1976, the trial court in the instant case properly refused to allow a collateral attack on that judgment.
Appellant next contends that the Park District should have been precluded from presenting its sheriff’s deed to the property in issue in appellant’s proceeding to secure a tax deed. The basis for this argument is a statement made by an attorney for the Park District in an unrelated proceeding to the effect that the Park District had no interest in the subject property. Appellant argues that, based on this statement, the rules of waiver and estoppel should have precluded the Park District from presenting their sheriff’s deed.
The statement which is the subject of this contention was made on October 27, 1977, in a hearing on appellant’s petition to be appointed receiver of the property in issue. The Park District appeared at that hearing by its attorney; who represented to the court that the Park District “has no interest whatever in the property.” By this statement, appellant contends that the Park District (1) waived its rights to the subject property, (2) judicially admitted that it had no interest in the property, or (3) should be estopped from asserting its rights to the property.
It is apparent that appellant’s waiver and judicial admission arguments must fail. The purported waiver in the instant case related to *35the Park District’s rights to the property in issue and was made by an attorney representing the Park District. An attorney in Illinois has no authority to waive any right of his client without the client’s express authorization. (County of Cook v. Patka (1980), 85 Ill. App. 3d 5, 11, 405 N.E.2d 1376.) In the instant case, there was no evidence that the Park District’s attorney was authorized to waive the Park District’s rights to the property in issue. Absent such evidence, the attorney’s purported waiver of the Park District’s rights was not binding on the Park District. The same reasoning applies to the judicial admission argument because judicial admissions are merely a species of waiver. See Wigmore, Evidence sec. 2588, at 821-22 (Chadbourn rev. 1981).
As with the waiver and judicial admission arguments, appellant’s estoppel argument must fail because of the Park District attorney’s lack of authority. “A finding of estoppel against a public body is not favored. [Citation.] The affirmative acts which induce reliance by a party must be acts of the municipality itself, such as legislation by a city council, rather than merely the unauthorized act of a ministerial officer or a ministerial misinterpretation.” (American National Bank & Trust Co. v. Village of Arlington Heights (1983), 115 Ill. App. 3d 342, 347-48, 450 N.E.2d 898.) As we noted above, the Park District’s attorney was not authorized to waive the Park District’s rights to the property in issue and appellant was not, therefore, justified in relying on the attorney’s representation. “A person who deals with a governmental body takes the risk of having accurately ascertained that he who purports to act for it stays within the bounds of his authority and *** this is so even though the agent himself may have been unaware of the limitations on his authority.” 115 Ill. App. 3d 342, 348.
Appellant also asserts that the court’s ruling on appellant’s petition for receivership is res judicata on the issue of the validity of the Park District’s interest in the subject property. It was in the hearing on the petition for receivership that the Park District’s attorney disavowed any interest in the subject property by the Park District. At the conclusion of this hearing, the court appointed appellant as receiver of the property. Appellant asserts that, in reaching its decision, it was necessary for the court to decide whether the Park District had any interest in the property. We disagree.
The Park District did not appear at the hearing on the petition to “contest” the petition as appellant asserts. Rather, the Park District appeared because it had received notice. Thus, at the hearing, the court was not presented with, and therefore could not have decided, the issue of the validity of the Park District’s interest in the subject property. Indeed, the statute pursuant to which the petition was filed *36does not require the court to rule on the validity of a party’s interests. All the court need determine is whether the holder of the certificate of purchase from the tax sale has filed the petition and whether the subject property is in danger of waste. (Ill. Rev. Stat. 1981, ch. 120, par. 734a.) After determining that the requisite parties have received notice of the petition, the court is free to appoint the holder of the certificate of purchase as receiver regardless of the quality of the interests of the other parties to the petition. (Ill. Rev. Stat. 1981, ch. 120, par. 734a.) The statute does not require the court to rule on either the validity or the superiority of those interests. Thus, appellant is mistaken in its assertion that the question of the Park District’s interest in the subject property was in issue. The court’s appointment of appellant as receiver in no way reflects on the Park District’s right to subsequently claim title to the property in issue.
Appellant also asserts that the Park District ratified, or at least acquiesced in, the purported waiver by its attorney of the Park District’s interest in the subject property, thereby waiving its rights to the property in issue. But the evidence of ratification or acquiescence cited by appellant are all instances of inaction by the Park District. These instances include the failure (1) to obtain a sheriff’s deed, (2) to defend against the demolition lien foreclosure action, (3) to prevent the November 16 foreclosure sale, or (4) to redeem from that sale. Such instances of inaction, however, do not constitute ratification. Cf. United States ex rel. Baez v. Circuit Court (N.D. Ill. 1975), 395 F. Supp. 1285, 1287 (client’s failure to object to attorney’s waiver of client’s right does not bind client to attorney’s actions); County of Cook v. Patka (1980), 85 Ill. App. 3d 5, 13, 405 N.E.2d 1376 (inaction insufficient to work an estoppel against county).
Appellant’s final contention concerns the trial court’s finding that appellant failed to give the requisite notice to the Park District of the petition for a tax deed. This failure was cited by the court as the basis for denying the petition. Appellant contends that, under the circumstances, the Park District was not entitled to personal notice and that notice by publication was sufficient.
“[Pjarties interested in the premises” which are the subject of a tax sale must be given notice of the sale and of the expiration of the period of redemption. (Ill. Rev. Stat. 1981, ch. 120, par. 744; see Ill. Const. 1970, art. 9, sec. 8(b).) The notice of the expiration of the period of redemption must be given not less than three nor more than five months prior to the expiration date. (Ill. Rev. Stat. 1981, ch. 120, par. 744.) “[O]wners, occupants and parties interested in the premises” must receive personal notice; “unknown owners or parties inter*37ested” in premises may be served by publication. (Ill. Rev. Stat. 1981, ch. 120, par. 744.) A purchaser at a tax sale is not entitled to a tax deed at the expiration of the period of redemption unless notice is effected in strict compliance with the above requirements. Ill. Rev. Stat. 1981, ch. 120, par. 744; see In re Application of Cook County Collector (Petition of Ohr) (1981), 100 Ill. App. 3d 178, 179-80, 426 N.E.2d 947.
In the instant case, the Park District received an enforceable interest in the property in issue as a result of the order of January 9, 1976, which directed that a sheriff’s deed to the subject property be issued to the Park District. Despite the fact that this order was never vacated or reversed, appellant contends that the Park District’s interest in the subject property was extinguished by the statement of the Park District’s attorney that the District had no interest in the property. But as has been discussed earlier, the attorney was not authorized to waive the Park District’s interest and appellant was not justified in relying on the attorney’s purported waiver. Nonetheless, appellant cites the purported waiver as the basis for her failure to give the Park District the requisite personal notice of the petition for a tax deed. According to appellant, as a result of the purported waiver, she treated the Park District as an “unknown party” in the petition for a tax deed, and, accordingly, service was made by publication only. But appellant had actual knowledge of the order of January 9, 1976, which she was not free to ignore despite the purported waiver. (See In re Application of County Collector (Petition of Burdash) (1977), 48 Ill. App. 3d 572, 588, 362 N.E.2d 1335.) Based on appellant’s knowledge, the Park District was a party interested in the premises and was therefore entitled to personal notice of appellant’s petition for a tax deed. (See Ill. Rev. Stat. 1981, ch. 120, par. 744.) Because personal notice was not given, the trial court properly denied appellant’s petition.
For the reasons expressed herein, the judgment of the circuit court is affirmed.
Affirmed.
PERLIN, J., concurs.
