Dear friend, the problem now is how should I fix this problem
You must do what I already said twice: GSX will tell you the name of the AFCAD in use in the Parking customization page. Just go there, read the name of the .BGL, and see if it's the one that comes with the scenery.
If it's not, you can be sure nothing will work correctly. So, first see if you DO have an AFCAD coming from another product which is conflicting with your scenery and THEN, after GSX has told you WHERE IT IS and HOW IT'S NAMED, you will know what's causing the conflict to begin with, and where to find the offending file.
Once you know where the offending file is, you must remove it. When the sim is not running, of course.
Please advise otherwise the GSX Is unusefull!
The problem doesn't have anything to do with GSX. You would want to fix every AFCAD conflict in any case, even if you don't have GSX, otherwise lots of things will be affected, like AI parking in the wrong places, ATC assigning you to the wrong gate and the wrong paths, etc.
The real cause is the conflict caused by the wrong file for your airport, and it's something you should fix. GSX it's just another victim of it...
