Symptom:
Internal error: print mode error (-7)
With newer versions of Caldera it will set the Quality to "Default" instead of the actual quality recognized by the printer.
Problem:
This error is caused by a media setting mismatch between driver and printer.
Solution:
Stop the driver from running first
Settings Tab > Server Admin > highlight the printer > Stop Server (password is caldera)
Now delete all files named *FB* in /opt/caldera/lib/shared folder.
Start the printer driver (you will have to do it twice) by double clicking the printer icon in Caldera (First time it will tell you the server info has changed).