I've had an app running about 1 year on a clients server which uses mscomm32.ocx
Recently they moved to a new server and reinstalled from my installer program and it continued to work just fine.

Ironically I've just rebuilt my development machine and made a minor change (just a text string) to the main .exe of the application. I runs fine on my machine. However on the clients machine this new .exe gives
Ole Error 0x80040154 Class not registered.

However the Mscomm32.ocx is registered on that machine. We're right now putting the old version back - hope to God that works :-)

What the heck is happening here? I'm stuck. And this is a critical app.