Anyone seen this before and have any idea what to do to fix it?

I have a screen that uses mscomm32.ocx to read values from a scale. When the user logs in to the PC as the administrator it works fine. If they log in as a regular domain user they get an error that the ActiveX has not been registered.

I have manually registered it (and the fact that it works when the admin is logged in shows it is registered).
This is on a Windows XP machine logged into a domain.