Have you checked to see if you have two rendering systems? If so, try switching to the other one. If you don't, go into the Ogre.cfg file in your FeralHeart folder and change the "OpenGL" in the first two lines to "Direct3D9" and see what that does.
Have you installed any sort of mod on it? Also this may be a longshot, but check your particles folder and delete anything ending in _0 or _1. Usually that happens only after making maps but couldn't hurt to check.