Classic British Flight Sim

I've downloaded AIFP so as to make some flight plans - first time in years and can't get it to open up after extraction. I'm getting the 'can't find FS9 in the registry' type message which is probably because I have FSACOF installed outside Microsoft Games and Program Files on my hard drive. Is there a simple solution?

It normally picks it up whatever the install path is. Mine was installed on e:\FS9 and it found it no problem. Have you tried right clicking and running as administrator?

Yes I've tried that but to no avail I'm afraid.