I am playing around dot net nuke and the first error I ran into trying to open my dnn 4.9 project in Visual Studio in Vista
this computer is not configured for iis 6 metabase and iis 6 configuration compatibility
Here is the fix
Control Panel –> Turn Windows Features On and Off
internet information Services --> check the box for IIS 6 Management Compatibility
Be warned this took a solid 5 minutes on my machine.
Have fun!