W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: http://archive.ubuntu.com hardy-proposed Release: 下列签名无效： BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>

W: 无法下载 http://archive.ubuntu.com/ubuntu/dists/ ... ed/Release

W: 有一些索引文件不能下载，它们可能被忽略了，也可能转而使用了旧的索引文件。
W: 您可能需要运行 apt-get update 来解决这些问题
_____________________________________________
0、系统是u8.04
____________________________________
1、
＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿

按论坛的方法：

gpg --export --armor 437D05B5 | sudo apt-key add -

gpg --keyserver subkeys.pgp.net --recv 437D05B5

还是不能解决。
＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
2、源是官方的源

#Archive.ubuntu.com更新服务器（欧洲，此为官方源，电信网通用户使用
deb http://archive.ubuntu.com/ubuntu/ hardy main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse
#推荐所有用户加入 ubuntu-cn 源
deb http://archive.ubuntu.org.cn/ubuntu-cn/ hardy main restricted universe multiverse
deb http://ppa.launchpad.net/tualatrix/ubuntu hardy main #ubuntu-tweak
deb http://download.virtualbox.org/virtualbox/debian hardy non-free #virtualbox

请帮解决一下。

你这俩命令顺序错了

必须先receive公钥才能添加

不应该出现这种情况的

我执行的顺序对，在贴子上，打错了（复制错了）。