Open Windows Explorer and go to C:\Users\YourUserName\AppData\Roaming\Virtuali\Airplanes and look for the CS_B737-200 folder. If you find it, delete it (also delete or remove the gsx.cfg file from the FSX\SimObjects\Airplanes\CS_B737-200 folder). Start FSX, load the 737-200 and start GSx, see if it sets it up again properly. As far as I can remember, the location of the airstairs and cargo loader etc. are originally set by the [exits] entry in the aircraft.cfg. They are in the wrong place within the aircraft.cfg so they may need to be changed. I changed them in the aircraft.cfg myself, but it made no difference, so to get GSX working correctly, I had to edit the locations myself. It works fine for me now, but if I call the jetway, it stope in the centre of the plane (above the wings because it is reading the [exits] info in the aircraft.cfg).