If you're using the .NET Framework and seem to have strange exceptions or hangs that you can't track and resolve, you need to consider the following .NET Framework 1.1 Hotfix Rollups (by querying support.microsoft.com for: framework 1.1 hotfix rollup post-service pack):

Availability of the .NET Framework 1.1 Post-Service Pack 1 hotfix rollup package for System.runtime.remoting.dll
Describes the availability of the .NET Framework 1.1 Post-Service Pack 1 (SP1) hotfix rollup package for System.Runtime.Remoting.dll.
http://support.microsoft.com/default.aspx?scid=kb;en-us;887543
 
Availability of the .NET Framework 1.1 Post-Service Pack 1 XML Web services and XML Messaging hotfix rollup package 8
Describes the bugs that are fixed in the .NET Framework 1.1 Post-Service Pack 1 XML Web services and XML Messaging hotfix rollup package 8.
http://support.microsoft.com/default.aspx?scid=kb;en-us;890673
 
 
 
Availability of the .NET Framework 1.1 Post-Service Pack 1 hotfix rollup package for Mscoree.dll
Describes the availability of the .NET Framework 1.1 Post-Service Pack 1 (SP1) hotfix rollup package for Mscoree.dll.
http://support.microsoft.com/default.aspx?scid=kb;en-us;887559
 
Availability of the .NET Framework 1.1 Post-Service Pack 1 hotfix rollup for Smartnav.js
Describes the availability of the .NET Framework 1.1 Post-Service Pack 1 (SP1) hotfix rollup for Smartnav.js.
http://support.microsoft.com/default.aspx?scid=kb;en-us;887560
 
Availability of the .NET Framework 1.1 post-Service Pack 1 hotfix rollup for MsCorLib.dll, for MsCorSvr.dll, and for MsCorWks.dll
Describes the availability of the .NET Framework 1.1 post-Service Pack 1 hotfix rollup for MsCorLib.dll, MsCorSvr.dll, and MsCorWks.dll.
http://support.microsoft.com/default.aspx?scid=kb;en-us;890340