Error while looking for updates

view story

http://askubuntu.com – Everytime I try to check for new updates, I always get this error message : W:Failed to fetch http://ppa.launchpad.net/pmcenery/ppa/ubuntu/dists/precise/main/source/S... 404 Not Found W:Failed to fetch http://ppa.launchpad.net/pmcenery/ppa/ubuntu/dists/precise/main/binary-a... 404 Not Found W:Failed to fetch http://ppa.launchpad.net/pmcenery/ppa/ubuntu/dists/precise/main/binary-i... 404 Not Found E:Some index files failed to download. They have been ignored, or old ones used instead. And I get a message telling me to check my internet connection, I am connected (HowTos)