Strange, I haven’t seen that before. On the star ratings tab all you need to do is check the checkbox for star ratings. It should be part of the form.
There are some installs where the preview does not work for star ratings, I have no idea why. Could that be the case?
Also, the star ratings are shown by default in the metabox behind the
.... You can change the location to be above the entry if you want that. Does that help?