It doesn't sound like operator error to me, but I don't have that particular machine. I am wondering if the needle is inserted properly? In any machine, the needle needs to be inserted correctly, all the way up, or you can get odd problems. Also, you need to be using the correct needle for the machine. I would double check that the needle is the correct one, then remove and re-insert it (or a new needle) and see if that solves the problem.