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 this folders:
%APPDATA%\Virtuali
%PROGRAMDATA%\Virtuali
- Reinstall all the FSDT products, and be sure you only use the latest installers on our site, not some older download you might have downloaded in the past.