Ok, first of; here\'s what I did:
I ran into the same error today after uninstalling .NET 4.5/Visual Studio 11 Dev Preview, then installing ASP.NET MVC 4 Beta (this is before Feb 29th when the updated VS 2011 Preview drops).
Since I uninstalled .net 4.5, you just need to do an "aspnet_regiis -i" to ensure the .net framework (4.0) is set up with IIS 7.x this worked for me.
Edit: This will work if you uninstall/then manually install Visual Studio 2012 RTM as well.