3D camera tracker, animated character bounces all over screen?

So I've been trying to follow some 3d camera tracker tutorials to the tee but I keep having the same problem. When I go to render the video instead of the character staying in a fixed spot it starts to bounce all over the video.

This is the main tutorial I've been trying to follow;

http://www.computerarts.co.uk/tutorials/3d-camera-tracking-after-effec ts-cs6?page=1

My error rate is only .73. I can't figure it out...