You may want to check the "materials" folder in the FeralHeart folder. See if terrain.cg, the terrain material file, and terrain.program are in it. If not, here's a link to the default materials folder with the three in it:
http://www.mediafire.com/download/c0p7f6q751e4kym/materials.zip (http://www.mediafire.com/download/c0p7f6q751e4kym/materials.zip)