lammert - 11:42 pm on Dec 13, 2012 (gmt 0)

This "Idle - Filter failed" problem seems to be a confirmed bug in Ubuntu which has been reported by multiple users in the last few weeks. It may have been triggered by a recently pushed update.

More information here on the Ubuntu bug tracker: https://bugs.launchpad.net/ubuntu/+source/cups/+bug/1080187