Hi,
I have win 7 32 bit and Interaction FAX printer driver is installed fine and I can send and receive FAX, so most likely you have a 64 bit install and in that case there are 2 solutions.
1) upgrade to 3.0 when SU 11 is available.
2) reinstall the Win 7 PC's with 32 bit rather then 64.
Hope this helps to make a decision.