I have a .NET 3.5 Web application on VS 2008 SP1 running on Vista Ultimate 32 SP1. I created an Application under the Default Web Site. So the url to the app is \"http://localho
Installing Urlscan and changing the urlscan.ini with these changes solved the problem.
In ALLOWEXTENSIONS Section add .aspx and in ALLOWVERBS Section add DEBUG.
Don't forget to restart IIS.