When did this start happening? Is it recent or longstanding?
In case it started with the newest update to Jaws, it's very important (and very easy to overlook) to destroy your personal Jaws scripts folder whenever you update. This allows Jaws to make use of all the new files in the update. If you have old files hanging around Jaws silently uses these which means you end up with a partial update which can lead to version mismatches.
What folder am I talking about? Mine, on Windows 7, is: c:\users\lmaschm\AppData\roaming\Freedom Scientific\Jaws\14.0. I destroy the 14.0 part, and of course lmaschm is my personal ID.
In case this step has been skipped, it's very easy to recover from the error. Just destroy the 14.0 folder and recreate everything using the Jaws utilities.
"Never imagine yourself not to be otherwise than what it might appear to others that what you were or might have been was not otherwise than what you had been would have appeared to them to be otherwise."