You deploy a Microsoft ASP.NET 1.1 Web site on a Web server. When the Web site is under a heavy load, an access violation occurs. Then, the application pool that contains the Web site is recycled.

For example, this problem occurs when many users access the Web site at the same time.

This problem occurs because of an issue in the SessionStateModule.PollLockedSessionCallback method. Sometimes, an instance of the SessionStateModule object is reused by several Web requests at the same time. When one Web request is completed two times, a NullReferenceException exception occurs. Then, an access violation occurs.

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

To apply this hotfix, you must have the Microsoft .NET Framework 1.1 Service Pack 1 (SP1) installed on a computer that is running Windows Server 2003 Service Pack 2 (SP2).

Restart requirement

You must restart the computer after you apply this hotfix if any affected files are being used when you install the hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.