CSLA .NET

Hi everyone.. I am running the project tracker and just ran into a problem.  It was working not too long ago but just stopped.  I don't know what happened.  Once I login (or try to open any other form than the main form i.e. add resource, edit project) I get the following error.

System.IO.FileLoadException was unhandled
  Message="The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)"
  Source="PTWin"
 

Any suggestions on why this is happening and how to fix it?

Thanks!

Hmmm. found an article on how to fix it and it worked, but I don't really understand what it did.

It says to disable the checkbox 'Enable the Visual Studio hosting process' in the form
Project > [Project_Name] Properties... > Debug

So, Is this supposed to be checked and something is broken, or did it somehow check itself?  Any ideas?