Technical issues with Heroes III.

Greetings, I've encountered the following problem: I have Heroes SoD 3.0 installed, I connect with a friend via Hamachi and we play for some time, but during or after a battle with monsters/heroes he crashes from the game. To be specific, first we patched the game to version 3.2, but the result was the same. We thought the problem was with Hamachi (we have Hamachi version 1.0.1.3, an old version), and here is the funniest part: after updating Hamachi to the latest version, created games stopped appearing altogether :) I've now downloaded Plan and will try it later; if that doesn't help, I think I'll download Heroes version 4.0.

The actual question is — what could be causing these crashes? In what area should I look for a solution?