I've done everything correctly now, I still had he problem, then the map maker wouldn't even work without crashing. I uninstalled and reinstalled. Then, I go to put in my new height map and as soon as I type in the name, the game crashed. Like I said, I triple checked all the properties of the map, and it's all running as it should except for the fact that it wont accept any of my height maps. D:
And yes, I painted over watermill.