Game crashes: questions and answers.

There's a problem... Heroes 5, Tribes of the East 3.1

I'm creating a GSC map - Size = Incredible, Difficulty = Hero, 3 computers. I'm playing as Orcs, and the game crashes randomly (usually after the first week) with an unclear error (as far as I can tell, it usually happens when trying to build something in a town)... and what's most unpleasant is that when I try to load an autosave or any other save file for this game, the game crashes again.

I can play online and in campaigns without any problems, as well as in other GSC maps...

I need help, as I don't even understand what this strange error might be related to.