fix the string warning raises

lib/virtual/compiler/basic_expressions.rb

@@ -39,7 +39,7 @@ module Virtual
 
       def self.compile_modulename expression , method
         clazz = Parfait::Space.object_space.get_class_by_name expression.name
-        raise "uups #{clazz}.#{name}" unless clazz
+        raise "compile_modulename #{clazz}.#{name}" unless clazz
         to = Return.new(Reference , clazz )
         method.source.add_code Set.new( clazz , to )
         to