Animation problem

I'm trying to replace the Garithos's horse with a mammoth. I scaled it all down and reporpotioned everything. I copied the first geoset, put the mammoth vertices, normals, faces, ect.. instead of the the original. I fixed all the textures. I left all the matrices there. But in animations nothing on the mammoth moves, the whole model just rotates or does nothing. Is what I'm trying even possible? I included the mdx, i know its off center and stuff but I was just doing a quick test before i put work into it.

And now look - all I did was scale the whole model down and scale away the weapon, shield, and head. And now the entire model isn't animated properly, it just rotates up and down. Here's the new one.

edit: added a picture. What's wrong??

Well, i rather say upload images instead of the mdx file...