This is caused by corruption of the FSUIPC files and can be corrected
- Go to the Flight Simulator 9/Modules folder and delete
the FSUIPC.dll, FSUIPC.txt, FSUIPC.cfg and FSUIPC.key
- Go to Peter Dowsons website and download the latest version
- Place the FSUIPC.dll file in the Flight Simulator
9/Modules folder and fire up Fs9 and the problem should be solved.