Close your solution, shutdown IIS, go to:
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\
And delete all of those files. Then restart IIS and try it all again.
Close your solution, shutdown IIS, go to:
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\
And delete all of those files. Then restart IIS and try it all again.