I solved the crashing height map problem, goodness. I made it all fancy 'n stuff, and went to test it. It worked great! Then I made a mask for it, and...
KA-BOOM!
The whole map is <4KIDZ> black. ;u; I placed the mask file into the same folder as the height map, it's a 513x513 PX canvas, one layer, RGB mode (Red, green, and blue colours), and it's a .PNG. I'm not sure why it's black I need help making it colourful, anyone have any ideas? .o.