I know this is already solved, but just in case this happens again, this is what caused a similar problem for me:
If you look in Feralheart > media and check all the subfolders(especially Sky, My_Objects, and Particles), look out for files ending in _0,_1,_2, or something like that. These are called double particles, and they can royally screw up your game, so if you delete them FH usually starts working again :3