hello Pawel,
you must install the mod in this folder : ...\Documents\My Games\Sid Meier's Civilization 5\MODS
what do you mean with custom map ? if it's a map made by you or another player perhaps it's the map that has a bug?
If not, it is possible that the mod is not compatible with some maps.
It is probably because of the new resources but I really don't see how to change this if it's the case!
Did you try the mod with a normal map from the game ?
you must install the mod in this folder : ...\Documents\My Games\Sid Meier's Civilization 5\MODS
what do you mean with custom map ? if it's a map made by you or another player perhaps it's the map that has a bug?
If not, it is possible that the mod is not compatible with some maps.
It is probably because of the new resources but I really don't see how to change this if it's the case!
Did you try the mod with a normal map from the game ?