This problem appears to occur primarily on 64-bit operating systems. Unfortunately the 757 Professional load manager was designed before 64-bit operating systems were introduced. On 64-bit systems, Flight Simulator 9 is installed into a different location: C:\Program Files (x86)\Microsoft Games\Flight Simulator 9. The load manager is unable to locate it there. The problem can be resolved by making a change to the registry.
Please contact the support team using the link found at the bottom of this page for assistance with this problem.