The back of the sholder should be binded to the spine, not the sholder bone. Also be careful not to bind any shoulder vertecies with the head.
The waist and front groin area should be binded to the AIRNGR[k] bone, and the buttocks and knees binded to the thighs.
The DUM MVR, as probably suggested in the naming, is mearly a dummy bone for world placement and never should be part of your WWSKIN bonelist.
If you're still getting deformations, post a pic of it
