Game crashes: questions and answers.

Heroes V: Tribes of the East 3.1; TE 5.5; IRMG map, huge, template - M3. We are playing with a neighbor on the local network, and the game crashes periodically with a message about stopping. The computer is not bad, but old, and the graphics settings are at their lowest. The hard drive is damaged, but I doubt that's the cause, as the game would run much worse in that case. I would be grateful for any help!