HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

I doubt it's the HD mod, but I haven't found any other themes with similar issues.

Yesterday, I played with someone, and we connected, but first, he couldn't generate a random map when he was the host, and then neither could I. Now, I can't generate it at all, even in single-player; the error message says "Cannot create Random_Map.h3m in data directory," but my opponent can.