I am following a tutorial on modeling a human body, and am working on the torso. The only problem is, when i smooth my polygon torso, i get a really weird effect. If you look at the attatched image, you can see the origional poly torso on the right, and the messed up smooth version on the left. I opened the scenes support file that had the same poly torso, and that one smoothed fine. What is wrong, do i have messed up edges or vertices or something?

Thanks

David