This error occurs when you use a version of PS-9000 which cannot be used with the QL-500/550.
Check if your version of the PS-9000 can work with the QL-500/550 by:

[Check Method]

1. Check the PS-9000 box to see if the QL-500/550 is on the list of compatible machines.
   
   
   

2. Check the label on the back of PS-9000 to see if "V001" or "R002" is identified.
   
   
   

3. Check the version of the PS-9000 with an internet browser.
   If it lists Ver.1.2.0 or earlier, then it is not compatible.
   
   

[Solution : If the version of PS-9000 is not compatible with the QL-500/550]

The firmware can be updated to allow the PS-9000 to be compatible with the QL-500/550 by downloading the file from the Download Page. Update the PS-9000 by following the directions in the Manual/readme, that is also downloaded from the Download Page.