I have been following McCoy Buck's rigging tutorial, but I'm having a problem and I can't figure it out.
I'm having a problem with artwork not binding to a skeleton. When the arm I'm working with bends, it's not deforming at the elbow. The whole arm rotates.

I've tried reparenting but that didn't work. I want the shoulder to stay still and the arm to deform at the elbow. What am I doing wrong?
Any help or suggestions would be greatly appreciated.
Thanks!