GSX has been crashing when I go to pushback in FSX. It keeps telling me to install latest program. I have done that twice.
If it's telling you to do that, it means you haven't updated it.
Today when I tried to update the update stopped when it got to the baggage truck section and locked up. Happened twice.
This seems to confirm it. If the Live Update cannot complete, surely something will not work, since you are left with a mixup between new and old files.
The most likely cause for the Live Update not completing, is your antivirus mistakenly blocking it. Try to exclude the whole Addon Manager folder from the antivirus scanning, and run the Live Update again.
Alternatively, try the full GSX installer, but still configure the antivirus to exclude the Addon Manager folder from scanning.