Custom Blender Monsters for Amnesia

[The MasterNater]

Alright, I'm back. I tried Spelos's technique. The first thing I tried it on was a simple ceiling fan that was animated to rotate, and it actually worked just fine, exactly how it worked in blender.

I tried it out on my custom monster and it works... but its extremely broken and nowhere near usable. Although it's animated just fine in blender, the animation in the model viewer is vaguely the same, random polygons move that weren't supposed to while others that were supposed to move, don't. It just looks really distorted.

Any ideas on what might have gone wrong?