Sorry to hear you are having trouble.
It would help if we could see what's in your debug.err file, it is located in \Documents\My Games\GC3 or \Documents\My Games\GC3Crusade
And a savegame, savegames are located in \Documents\My Games\GC3\Saves or \Documents\My Games\GC3Crusade\Saves
If you could upload them to a cloud service (DropBox, Google Drive, One Drive) and post a link here, the developers can take a look at them.
Thank you for your patience and patronage.