1. Back up any presets or maps that you made or downloaded, save them to your desktop. (If you don't have any, that's fine too.)
2. Uninstall FH using the uninstaller in the FH folder.
3. Delete the FH folder.
4. Reinstall FH.
5. Put your maps and presets back in, then try Map Maker again.
Hopefully this helps. c: