Hello Jon Vance,
This error is not one that appears in our known errors/bugs. I am pretty sure the error is being passed along from the data engine of the data source but please contact our Tableau Support via the case creation process at http://support.tableau.com for further assistance debugging the issue if this is still occurring.
This is one of internal (very internal) extract parsing error codes and my initial guess would be that something went wrong with either previous extraction or TWBX packaging.
Would you be able to share your TWBX either here or with our support folks?
Try recreating your extract and point the workbook to the new extract. That might resolve your problem.