Hi all

I have recently pieced together a photo memory quilt of my grandmother. I want to stipple quilt it, but I am running across a problem. The dang thread keeps breaking! I've practiced on some scraps and I've got the stipple part down. The tension is good (thanks to Jenny's tutorial). It looks great except for I can't sew more than about 10 inches without the thread breaking. It seems to be locking up/sticking (not sure of the term) in the step 2/5 part of threading the upper part (again, not sure of the term). It's not the take up lever, but the step before that. I have a brother xl2610 sewing machine. It's just a lap quilt, so it's not anything ginormous. I'm just not sure what I'm doing wrong. Can someone help me?

Oh, the thread I'm using is Coats and Clark, 30wt, mercerized cotton and a size 14 needle.

Thanks!