OK I want to make this as painless for you as possible so here's some more information that might help you.
1) I thought the problem might have been that I was using location keys. I deleted the location keys and tried it just using the rotation keys of the armature. That didn't work.
2)I tried exporting the mesh without the armature. That worked, so the problem can't be with the mesh, it HAS to be with the armature.
3)The mesh is parented to the armature, and the vertex groups are split into two different sections, the WEST WING, and the EAST WING.
4)There are no extra objects in the scene, and no materials. Just the Mesh and armature
Hope that helps somewhat. I really need to cross this bridge so I can get a move on with my game. I fear my development team might get restless if I don't figure this out soon.
Cheers
"What comes up, must come down. Except cheques, they bounce."