I'm not familiar with AccuPOS, but I have some thoughts.
Did the employee try to change the printer by opening the report in Crystal and the saving it back? If so, I suspect that the version of Crystal that was use is not the same version that the software was designed to run on and that is causing your problem. If that is the case you'll need to see if you have a backup of the report somewhere that you can reinstall in AccuPOS or you'll need to contact them for support.
If the user just changed the printer somewhere in the AccuPOS software without editing the report in Crystal, you'll also need to contact AccuPOS for support.
-Dell