I see this is an old post, hope you still have the machine. I have had a pfaff grandquilter 1200 for about 5 years and I have never had trouble with it. I had more trouble with the frame it was on. Make sure the roller is on the machine bed and that you have good quilting thread. I have used several kinds. I just up graded to a 18 by 8 sold under pfaff or viking made by tin lizzie. Im learning to use it. It is a lot more picky and likes to break thread. I will get it lined out eventually.
good luck and patience