Hi Rudi,
Please make sure that the targeted framework is .NET 4.0 and not .NET 4.0 Client Profile. In the Solution Explorer, right click on your WindowsFormsApplication and select Properties. Then change the target framework to .NET Framework 4.
Also, make sure to add reference to the following assemblies:
Nevron.Presentation.dll
Nevron.System.dll
Hopefully this helps.