So you’ve added the reference to Rhino.Mocks.dll, added the correct using statement, and keep getting a compile error stating that “The type or namespace name 'Rhino' could not be found (are you missing a using directive or an assembly reference?)”
Check your project properties –> Application -> Target framework. If it’s set to a “Client Profile” (.NET Framework 3.5 Client Profile or .NET Framework 4 Client Profile), Rhino won’t work. The proxy system built into Rhino needs the full .NET Framework.
Change the Target Framework to a “Full” framework, either the .NET Framework 3.5 or the .NET Framework 4 selections, and Rhino will be happy again. This only has to be done for your projects that use Rhino, not all projects in your solution.