Having this issue too. Theres a obvious issues with the map maker and I was wondering if there was a way to fix them.
Common errors I've had:
*After exporting a map, Feral Heart fails to even reach the KovuWorks image before crashing (fixed by re-installing but annoying)
*Missing .cfg files on old maps (Not sure how to fix this)
*Height map failures when heightmap image is set up correctly (i.e. It's 513x513, png, made with Gimp, one layer, is greyscale)(
Sometimes redrawing doesn't fix this and neither does lowering the white shades to slightly darker shades)
(Example of my heightmap image that doesn't work:)