I'm not going to say this is a stupid question :D This past week was the first time I used a walking foot. It came with the machine I bought about 2 months ago (a Brother CS-6000i), but hadn't had a chance to try it. Well all was going fine, just sewing along in the ditch, until the last row. All of a sudden, the entire foot started jumping up and down!! I checked to make sure all the screws were tight, tried again.... jump, jump, jump! Took it off and finished with a regular foot! Any suggestions? Thanks in advance!