I'm happy not to be the only living soul on earth with such problems ;-)

I'm using MCComm in one of my projects and encountered the same problems. As far as I know (after some long and tedious hours of researching), it all depends on the licensing schemes of foxpro (see MSDN Article Q139154).
What you must ensure, is that you have the same versions of OCX and eventually DLL on all machines. This can be a pain, if you have different OS versions ! Furthermore you have to register them (to install fox beeing the easiest way, but it's a bit crude :-)
What often helps is to create a setup with the wizard. The setup will then take care of the registration stuff...

good luck !

Kaspar

PS: plaese email me, if you found out more !