Technical issues with Heroes III.

In GR, when creating a game, an error occurred.

Does anyone know what this is and how to fix it?

I haven't encountered this specific issue, but I understand the general idea. Either the RandomMaps folder is missing (you need to create it) or an incorrect address for random maps is specified in some .ini file. However, I can't say which file needs to be edited. I searched for such a file in the game folder but didn't find it; it might be specified in the system registry.