I have problems with airports installed prepare3d v2 (areosoft lebl-lemd-lepa)
when i start gsx the prepare3d v2 crash. with standard airports in prepare3d v2 there are no problems.
Try to enable Logging in the Troubleshooting page of the GSX Settings page, then post the content of your Couatl.ERR file that will be created in your %APPDATA%\virtuali folder.
If the problem happens only at Aerosoft airports, the most likely cause are bugs in their AFCAD.