1. Make sure your map is 513 x 513 and greyscale.
2. Change your rendering system in options > video.
3. Go into C: >>> Feralheart >> media > particles and delete any ending in _0, _1, and so on.
Also, sometimes the greyscale can be very complex, causing your game to crash. Try altering it a bit so it's more, 'simple.'
Same goes for any meshes.
You could also try lowering your video settings.