Consider the following scenario. You install the MS07-040 security update. Then, you run a Microsoft ASP.NET 2.0 Web application that is built on the Microsoft .NET Framework 2.0. In this scenario, you may receive an exception error message that resembles the following:

Event Type: Warning
Event Source: ASP.NET 2.0.50727.0
Event Category: Web Event
Event ID: 1309
Date: 12/07/2007
Time: 10:24:38
User: N/A
Computer:
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 12/07/2007 10:24:38
Event time (UTC): 12/07/2007 8:24:38
Event ID: aa58f4d35bc547aeafd7c417967bdd8d
Event sequence: 8
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/1/Root/ApplicationDomain
Trust level: Full
Application Virtual Path: /Path
Application Path: D:\ApplicationPath
Machine name: ComputerName

Process information:
Process ID: ProcessID
Process name: w3wp.exe
Account name: NT AUTHORITY\NETWORK SERVICE

Exception information:
Exception type: EndPointException
Exception message: Type ‘System.Web.HttpHeaderCollection’ in Assembly ‘System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’ is not marked as serializable.

Note: This problem also occurs in the .NET Framework 2.0 for Windows Vista.