Roy,
Dd you ever find a solution to the add-on 4 installation problem? I just got my copy of add-on 4 and I'm having the same problem that you described. After running install, I get a message saying to install add-on 4 in Drive G (CD ROM drive). When I do, the CD ROM drive just keeps cycling off and on forever with the same message diplayed. Same as you described, I can cancel the message and run RF but the new Add-on planes are not there.
I don't think this problem is OS version related because I'm running Windows 98SE. Roy, or anyone else out there, is there a solution to this problem?
Bill S