mmm, no idea. try to put the material script in another place like: FeralHeart\media\materials
be sure you are selecting the mesh when changing the material.
and also write the exact name of the material.
check the material name i have put in this mesh
if you use mcafee antivirus, open the material script with notepad to be sure the material script has been donwloaded correctly, the file must not be empty.