W:GPG error: http://ppa.launchpad.net intrepid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A9BF3BB4E5E17B5, W:Failed to fetch http://extras.ubuntu.com/ubuntu/dists/quantal/main/source/Sources  404  Not Found
, W:Failed to fetch http://extras.ubuntu.com/ubuntu/dists/quantal/main/binary-amd64/Packages  404  Not Found
, W:Failed to fetch http://extras.ubuntu.com/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.