On updating Quantal 12.10,it says , check your internet connection
W:Failed to fetch http://ppa.launchpad.net/team-xbmc/ppa/ubuntu/dists/quantal/main/source/Sources 404 Not Found
W:Failed to fetch http://ppa.launchpad.net/team-xbmc/ppa/ubuntu/dists/quantal/main/binary-i386/Packages 404 Not Found
E:Some index files failed to download. They have been ignored, or old ones used instead.

team-xbmcis not updated for 12.10. You can disable that fromsoftware sources. – Web-E Jan 6 at 8:42