Installing the new map only in the Textures/Menus/Map/World folder, where it's supposed to go (this results in no changes at all);
Installing the new map in the Textures/Menus/Map/World and Menus80/Map/World folders (this gives me the map you see above);
Resizing the map using Gimp to 1024x1024 and putting that in the Menus50 folder (doesn't work);
Sticking the new map in all three Menus folders (gives me a blank white map with icons).
I'm using Large textures and 1024x768 resolution, along with DarkUI. The original map, as I said, works fine (most of the time; rarely it'll be blank with icons, and often the game will crash when I try viewing the map, even if there are only a dozen or so icons - this is a recent development that I'm also trying to figure out).
So, with all that... does anyone have any suggestions?