Ubuntu 11.10 更新(sudo apt-get update)时报错：

W: 无法下载 http://ppa.launchpad.net/tualatrix/ppa/ubuntu/dists/oneiric/main/source/Sources  404  Not Found

W: 无法下载 http://ppa.launchpad.net/tualatrix/ppa/ubuntu/dists/oneiric/main/binary-amd64/Packages  404  Not Found

W: 无法下载 http://ppa.launchpad.net/tualatrix/ppa/ubuntu/dists/oneiric/main/binary-i386/Packages  404  Not Found

W: 无法下载 http://ppa.launchpad.net/sevenmachines/flash/ubuntu/dists/oneiric/main/source/Sources  404  Not Found

W: 无法下载 http://ppa.launchpad.net/sevenmachines/flash/ubuntu/dists/oneiric/main/binary-amd64/Packages  404  Not Found

W: 无法下载 http://ppa.launchpad.net/sevenmachines/flash/ubuntu/dists/oneiric/main/binary-i386/Packages  404  Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.