I've deleted the map.rwm and map_heights.hgt together... and I haven't edited map_heights.tga. And I have been very sure to delete the newly generated map.rwm after any changes (all the time, just to be sure). The game loads fine, but after the regeneration of map.rwm, I get a KTM, then the Imperial Campaign can no longer be selected...

The map is the original RTW war map - no mods are installed at all.