I'm quite new to Blender and have been trying to get into camera tracking for my movies for a while now. I have gone on lots of forums and watched many tutorials but can't fix this problem. Whenever I track a scene and simply test it with a cube, the cube starts moving around and spinning about and things like that. I simply don't understand as I'm very new to this. I have got a movie clip off of a YouTube tutorial and tried to add a cube to test it and the same thing happened. I'm not quite sure how else to explain it, but the cube just keeps moving around.
Please help, Thanks.
EDIT:
Here's the file:
NFT