What the...

[meeeea]

  So... I exported my map and went into FH to play, but before it loads, it says "FH.exe has stopped working". I checked my particles folder: It didn't have doubles. I re-installed FH, it still didn't work. Help? Please? D:

[CloudFish]

Make sure to check your object folder for doubles too, probably in "my_objects".

[Necromancy]

Try uninstalling FeralHeart and deleting the FeralHeart folder (if you have any presets, etc. that you really need, save them, although one of your maps or presets could be the problem if you have any), then reinstall.
If this doesn't work, you may need to change your RenderSystem. I'll see if I can remember how to do that if deleting the FH folder and un and reinstalling doesn't work.