The problem comes from Darky's coding, more specifically, Nozdramus' abilities. Some of them have local variables with the logical name "lightning". Unfortunately, in 1.12 or maybe earlier/later versions, the object type lightning was introduced by Blizzard. Therefore, the map crashes because the trigger is not disabled (even though you don't select Nozdramus, the bug still exists because the code exists in the map). Only maps 1,2,3 and 5 do not cause the bug, as they do not contain any dragon, and therefore, the spells triggers do not exist.