ubuntu 11.04中update出现错误，恳请高人指点，^_^

[lozi0425]

#sudo update
出现错误：
……
错误 http://ppa.launchpad.net natty/main Sources
404 Not Found
错误 http://ppa.launchpad.net natty/main amd64 Packages
404 Not Found
忽略 http://ppa.launchpad.net natty/main Translation-zh_CN
忽略 http://ppa.launchpad.net natty/main Translation-zh
忽略 http://ppa.launchpad.net natty/main Translation-en
忽略 http://ppa.launchpad.net natty/main Translation-zh_CN
忽略 http://ppa.launchpad.net natty/main Translation-zh
忽略 http://ppa.launchpad.net natty/main Translation-en
忽略 http://ppa.launchpad.net natty/main Translation-zh_CN
忽略 http://ppa.launchpad.net natty/main Translation-zh
忽略 http://ppa.launchpad.net natty/main Translation-en
W: 无法下载 http://ppa.launchpad.net/tualatrix/ppan ... ce/Sources 404 Not Found

W: 无法下载 http://ppa.launchpad.net/tualatrix/ppan ... 4/Packages 404 Not Found

然后更新管理器 也无法更新。到底什么意思，请教大家，^_^

[qy117121]

有些ppa上的软件还不支持11。04