Hi Jeanne,
Do you have the Hinterberg frame and Voyager 17 setup? There is a yahoo group for hinterberg.
I have a that exact set up mentioned above and it sounds like either your tension it too tight, top, bottom or bother. Are you moving the machine too fast as opposed to the speed of the machine, causing the thread to break? Is your timing off, is your bobbin in the right way? Is your thread old? Maybe your thread and bobbin thread don't like each other. Are you using a spool or a cone of thread? If you are using a spool, do you have the spool in a horizontal position or upright position? If in an upright position, do you have the split end on the bottom? Is your needle in the right way? These are just a few ideas. Hope this helps to find the problem.
Sandi