Sometimes I think it is just sheer cussedness, Quilter - anything to prevent you from being able to sew! Seriously thought, re thread everything, even if you think you already did that. And I mean right from the thread spool down to the needle. I kept doing that once, but didn't realise that my thread wasn't in between the tensions discs correctly. Are you using the same thread top and bottom? Sometimes using a different thread in the bobbin doesn't work so well when quilting. I hope you can sort it out soon, and get back to the sewing.