Question : That assembly does not allow partially trusted callers

I have an application that is runs from a GIS system.  These means that we provide a .NET assembly that implements a specified interface.  This all works fine when the application is run on a work station.  When the same application is run in a Citrix terminal server envionment, we recieve the message "That assembly does not allow partially trusted callers" when the GIS system is attempting to load our function.  We have rebuilt the application using the "[assembly:AllowPartiallyTrustedCallers]" syntax and have verified that the attribute is present by loading these assemblies via reflection calls.  Unfortunately, these asssemblies also generate the same error.  Does anyone have any idea what the root cause may be?

Answer : That assembly does not allow partially trusted callers

I problem has been solved.  The real problem was a security issue related to accessing the assemblies via a network share.  Used caspol.exe to create the necessary Code Group to grant the access privileges required.