Index: Engine.cs
===================================================================
--- Engine.cs	(revision 687)
+++ Engine.cs	(working copy)
@@ -278,6 +278,11 @@
 						   call.DeclaringType.IsValueType);
 			adcStubType = GetTypeDefinition (ntype.Namespace, ntype.Name);
 
+			if(adcStubType==null)
+				throw new EngineException (string.Format (
+					"No match found for the ADC stub class `{0}'",
+					ntype.Name));
+
 			// Find the equivalent ADC layer method
 			foreach (MethodDefinition def in adcStubType.Methods) {
 				if (def.ReturnType.ReturnType.FullName == call.ReturnType.ReturnType.FullName &&