I'm sorry, but I cannot reproduce the problem. Try a full uninstall, this way:
- Uninstall every FSDT product you have, both sceneries and GSX. Reply YES to the question "Do you want to remove the Addon Manager" ?
- Remove these folders:
%APPDATA%\Virtuali
%PROGRAMDATA%\Virtuali
- Reinstall all the FSDT products, including GSX, which is required by basically all our sceneries, and be sure you only use the latest installers on our site, not some older download you might have downloaded in the past.