Even though it is called the Visual C# 2005 Express Edition and they explicitly point you to the Visual Web Developer 2005 Express Edition for web site development, the Visual C# 2005 Express Edition (and no doubt others) will still upgrade your ALL YOUR ASP.NET VDIRS to version 2.0.40607.0 without asking.

You can go your %windir%\Microsoft.NET\Framework\v1.1.4322 directory and run:

ASPNET_REGIIS -r

to replace the ScriptMaps with ASP.NET 1.1, and you're back in business.