First, be sure you use the *current* GSX installer, not an old installer you downloaded in the past.
If with "updated to the latest version", you mean with the integrated Live Update, it's still not the latest version, if your original installation came with Couatl 2 (Live Update there is frozen to the latest Couatl 2). To be sure you have the latest version, you must download and install the current full installer, and then you can use the current Live Updates.
Also, whenever you report any problem, always indicate all the following:
- The airplane you use.
- The scenery in use.
- The gate used.
Also, maybe GSX is trying to tell you WHY you cannot start pushback, but if you turned down the Verbosity slider in the GSX Settings, you won't see the message, so you think GSX has stopped, but instead it's just waiting for some action on your part.