'Felhound' isn't a unit. There's a Fel Stalker, Fel Ravager and Fel Beast. The path you linked doesn't lead to either of these three units, and when I enter the path directly into the model file it shows up right in the editor, but never in-game. Unless I'm missing something rather obvious, I can't tell which of the three it should work with.
Edit: Nevermind. Found a working path.