Problems importing blender animations into Unity

I have a simple animation of an exploding cube, that I made with blender. I set up the animation in blender, and then exported it as a .fbx file into unity. When I look at the cube in the editer on the right, I see what I would expect to, exept when I try to play the preview, nothing happens. It goes throught the animation but nothing moves! When I put the prefab into the unity 3d editer, and click play, the cube just stands still. Anyone know how to fix this!?

Sorry if the description was a little long - Pie Lord