Thanks for your bug report, this is a gnome-cups-manager bug.
The problem is gnome-cups-manager looks for your printer model under Lexmark, since the Z600 isn't there it matches the one that closely resembles it: Z12.
Since the Z12 driver is not compatible with your printer this won't work.
Your printer needs a properietary driver from Lexmark that is not included in Ubuntu.
> Model Z12 is highlighted
Thanks for your bug report, this is a gnome-cups-manager bug.
The problem is gnome-cups-manager looks for your printer model under Lexmark, since the Z600 isn't there it matches the one that closely resembles it: Z12.
Since the Z12 driver is not compatible with your printer this won't work.
Your printer needs a properietary driver from Lexmark that is not included in Ubuntu.
Did you try the steps described here: http:// ubuntuforums. org/showthread. php?t=49714.