Have you tried just two pieces of fabric no batting with the walkig foot? If it is still messing up it is the foot. I don't think you could break it just not have it on right. I haven't used a walking foot in so long, but I think we've covered all the possbilites. Also you want to guide the material through, kind of assist it, but the machine should also be pulling. A friend told me once to have the quilt sandwich resting on your chest as you feed it through.