We would suggest verifying that you are using LaserWriter Utility 7.6.1 or 7.6.2. These are the only supported versions of the LaserWriter Utility for the LaserWriter Pro 810. LaserWriter Utility 7.6.1 shipped with the printer, however, a bug was found with that version which affects LaserWriter Pro 810 printers with PostScript fax cards installed.
These articles can help you locate the software update mentioned here: