Bug when upgrading from demo to full game

Hi there. We’ve tried the demo out for a few months and my son saved up enough money to buy the full version plus the expansions (aka the collector’s edition). However, despite the demo working just fine the full version does not start at all. When I attempt to start the programme It goes straight to an error message. The error signature says:

“AppName: gsb.exe AppVer: 0.0.0.0 ModName: gsb.exe
ModVer: 0.0.0.0 Offset: 001d71cf”

I’ve tried uninstalling the game and reinstalling it which didn’t work. I then tried deleting both the demo and the full version then reinstalling the full version. Again, no effect. Can you please advise me on how to make this game start?