I need to write a module for Apache. The server will be running under Windows and it looks that I will need to utilize some functionality which is implemented as COM.
Is this ok to use COM in Apache module or should I try to avoid this?
There is no inherent reason to avoid this. I recommend that you completely disconnect from the COM object at the end of the request, and uninitialize COM, in the first version. Once you have that working, you can start trying to preserve some state across calls - just remember that Apache's process and threading model may result in state not being preserve across requests.