Hi,

No, the type is not defined in another assembly, nor is there any other cached assemblies lying around.  

This is the code that fails:

The type SecSoaService.NFFIServiceParameters inherits from the abstract class ServiceParameters.
public ServiceParameters EditWebServiceParameters(ServiceParameters parameters)
{
   SecSoaService.NFFIServiceParameters param = null;
   try
   {
       param = (SecSoaService.NFFIServiceParameters)parameters; //exception is thrown.
   }
   catch (Exception ex)
   {
       System.Diagnostics.Trace.WriteLine(ex.Message);
   }

// test  
   try    
   {
       param = (SecSoaService.NFFIServiceParameters)(new SecSoaService.NFFIServiceParameters()); //no exception.
   }
   catch (Exception ex)
   {
       System.Diagnostics.Trace.WriteLine(ex.Message);
   }
   ...
}

From the watch window i extract the following:
parameters.GetType().Module.FullyQualifiedName  = "c:\\temp\\IFM\\Tool\\modules\\services\\secsoa\\SecSoaService.dll" string
and the
parameters.GetType().AssemblyQualifiedName  = "SecSoaService.NFFIServiceParameters, SecSoaService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=e9c77c3cc6a7a0ac"

And the param variable gets the following values after beeing assigned:
param.GetType().Module.FullyQualifiedName  =         "C:/temp/IFM/Tool/modules/services/secsoa\\SecSoaService.dll" string

param.GetType().AssemblyQualifiedName         = "SecSoaService.NFFIServiceParameters, SecSoaService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=e9c77c3cc6a7a0ac"

As you can see both types have the same Assembly Qualified name and the same Module FullyQualifiedName.

So as far as i can see these two types are identical!
The only thing that is different is the format of the FullyQualifiedName path.  

regards,
Lars