Ok, I have had this one a million times before and it\'s been answered 1 million +1 times before.
And yet, once again. I have 3 projects, A, B, and C, each a DLL. Each
I would make sure that your project has included the references to the assemblies.
I would check that the build order matches your dependencies
Finally, if everything is setup properly, you should see the following Build Order:
Doesn't look like this is your problem, but for completeness, I should add that another thing to check (if your project targets the .NET Framework 3.5 or above) is that the Target Framework for both projects match. If you are linking something that targets the Client Profile from a full version of the Framework, you will also get a 'not found' error: