Also, is it possible you might have manually copied the whole GSX packages to the Community folder, instead of having Symbolic links to it ?
Doing this will guarantee nothing will work because, the manually copied copy in the Community folder will be left outdated (the FSDT Update only updates the Addon Manager copy ) and will prevent the sim to see the copy that has been updated.
If you did this, REMOVE the copies in the Community folder, start the installer and click "Relink", so it will create the Symbolic links as it was supposed to.
A way to recognize if a folder is a real folder or a Symbolic link, is if it has a small arrow on its icon in Windows Explorer. If it has no arrow, it's a real folder, which is wrong and now how we install GSX normally so, REMOVE IT and in the FSDT Installer choose "Relink".
Then, run an update CHECK on GSX, to be sure you have the latest files.