Problem with saves in Heroes of Might and Magic V: Tribes of the East (pirated version).

Because the Russian language wasn't working for my friend, we figured out that the issue might be related to this. As it turned out, the problem was caused by the system language being set to Japanese in the computer's regional settings through the control panel. After changing it to Russian, my friend's game started displaying Russian characters correctly, and the save files started working again.

Problem solved.