Negativ. The GSX menu doesn't appear under Addons, only the Addon Manager.
Ok, so it's very likely a simple antivirus problem. Be absolutely sure:
- You have added the WHOLE Addon manager FOLDER to the antivirus EXCLUSION.
- You run the FSDT Live Update again.
Also, from your screenshot, it seems something's odd: you have a double entry for LH simulation, is this normal ? It might be an indication of a problem with your P3D settings, which might also be a reason why GSX is not working.