It sounds like either one of 2 things is happening..and they have both happened to me before. Either the weight of your quilt is pulling on the machine and you may need to fluff it up more and let the feed dogs pull it through by themselves OR....your thread is getting pulled too tightly before it goes into the machine. Is your quilt hitting your spool or something else hitting the spool that is not letting it pull of the spool smoothly?
If its not either of those...then someone else will have to help..I just take care of the simple "dumb" mistakes like I tend to make :wink:
Good luck!