Game crashes: questions and answers.

Hello. There's a strange issue with crashes during AI turns. I'm sure the system requirements aren't the problem, as I've almost completed three campaigns without issues. Heroes 5, v 1.6. The problem is that the game crashes during the AI's turn, prompting me to send a report to Microsoft. I first encountered this in the last mission of the first campaign; it crashed, I loaded the save from the previous day, and it crashed again. I suspect the AI was doing something that caused the crash. I loaded an earlier save, and everything was fine until that same date, and there were no crashes. Now, the same thing is happening in the campaign for Rai'lag, but much more frequently. What could be causing this, and how can I fix it? I downloaded the game; it's the Gold Edition.