Thanks to everyone with suggestions. I think we have figured out what the problem is, but not how to fix it ourselves. The machine will run beautifully if the throat plate is removed. Apparently, the feed dogs are hitting the throat plate. They appear to be too far forward (towards the sewer). We have downloaded the adjusters manuel and it does tell us how to move the feed dogs length-wise, by turning a screw on the bottom of the machine, but this has not seemed to make a difference. What are we doing wrong? Thanks so much for your help. I have looked on the web, but can't find an answer. Gina