Jerky animation.

I remember there used to be an issue where the circles under creatures and heroes moved in a jerky, rather than smooth, manner. I somehow fixed it back then, and I even found the solution on a forum.

When my computer crashed, I had to reinstall everything... and now I'm facing this problem again! By the way, the trees also move in a jerky way.
Does anyone know what might be missing? I installed DirectX 9.