Another thought is that there is too much or not enough pressure on the presser foot. My machine has a knob so that you can increase/decrease how much clearance there is between the feed dogs and the foot. I'm not sure I'd be using a walking foot on tiny little doll clothes anyway. I only use it when quilting in the ditch and sewing on binding. It helps feed all those layers of fabric and batting. For small things, I would use a my smallest clear applique foot or a zipper foot so I could see what I was doing better.