I have DotnetNuke loaded in Visual studio 2010. The 'use custom server' option under 'Start Options' is disabled. Why is it disabled? What does 'Use Default Web server' default to? How do I change what the default is? In earlier versions of VS i was able to switch between IIS and the internal web server (Cassini). Now it's more confusing in VS 2010!
Would the project type, Web Application Project vs Web Site project, affect the setting?
I've just had this problem on one of my projects that was setup to use IIS Express.
The solution for me was to right click the web site project and select the option to use the VS Server instead. The option to then use a custom server was then enabled again so I could point it to the IIS site I wanted to test against.