Achille,
ArchiCAD can give this error,
-if the MEP library is not loaded, or not the complete library is loaded
-if the MEP tools have wrong defaults, so all MEP related tools in ToolBox should have a valid MEP object as default (routing uses the defaults to create the system)
So I think this error is not related to TeamWork, check your tools and the library.
Regards,
Marton
Marton Kiss
Chief Product Officer
GRAPHISOFT