Hello, some VB books states that in order for a client app to reference an Active EXE class, Active EXE has to be running. But I found it to be contrarary. What I did was to open Active EXE server in one VB session, open the client in another VB session. Hit the run button on the client app, it makes the correct calls to the ActiveX EXE server no problem. However, if I start to run the ActiveX EXE in its VB environment first, and then try to run the Client app an error occurs. ("error code 430: interface not supported"). ??? Strange.