Perhaps this will save you a few headaches.
I installed the Visual Studio 2005 November CTP beta today. The IDE install went smoothly. When I tried to install the MDSN help files however I ran into a snag. The install stops and tells me I need to have XP SP 2 installed. What? Turns out the new MSDN archiver application is a .NET application and the MSDN installer checks for XP SP2 and .NET 2.0 before continuing.
OK, I install the SP2 on my Virtual PC and try again. Now I get an error stating that I need to update my .NET 2.0. What? I have .NET 2.0 installed, I just finished installing it!
Turns out the Setup.INI file is checking for .NET version 2.0.41119. The framework that was installed is version 2.0.41202.
Solution... change the contents of the INI file
[dotnetfx]
version=v2.0.41202