Windows Choppy mouse movement on Torchlight 2

I installed Torchlight 2 yesterday and the mouse was very unresponsive. It would jump and skip and sometimes not respond even at all. I finally managed to get it over the play button and it was a little better in game. although occasionally it started to act up again. this is on a 2010 macbook pro with 320m graphics. I havent seen anyone else post about this. The mouse works fine when the game isnt loaded. I dont know why its happening. Any help?