Ruthie,
Are you using monofiliment thread? My Bernina sewing machine does not like it at all. I have a 1260 and a 1530. Both of them will stitch for a minute or two with the clear thread and then it gets hung up in the bobbin case. I have tried several different brands no dice. On another forum they gave tips on differnt ways to use monofiliment that I have yet to try.
Let us know how you make out.
mpspeedy