Could be related with the new 10.8 and must be investigated. Please consider giving a call to your local support centre.
MAC OS.X 10.8 is not yet supported.
It's brand new.
You can still try this:
1. Remove the printer-queue on the mac
2. Click on add "OTHER" printer
3. Choose “IP Printer” from the first drop-down menu.
4. Afterwards select LPD/LPR from the second drop-down menu.
5. Put in the Printers IP address in the “Printer Address” window.
6. Double check that the queuename is empty.
7. Choose the correct driver/PPD file from the drop-down menu.
8. Click the “Add” button. Printer should now be installed with the old protocol and hopefully will work as intended. Though this is not guaranteed
This works on Printers not having support for OS X 10.7