Bob H wrote on Sep 14^th, 2012 at 9:01pm:

Mark, I tried the install again and still same problem. I am going to try something I read on another forum that resolved someone elses issue several years ago. I will uninstall FSX accelerator and install service pack 2. From what I have been reading there might be something with the acclereator and Vista,  that could be causing this problem. We'll give it a shot...

What about just doing a repair of Acceleration? Although I usually run a repair of FSX first, THEN run a repair of Acceleration, when I encounter problems in FSX. This can often sort them out. It will not modify any files that would cause problems with any 3rd part addons - At least it never has for me.