apt求助

我从http://debian.cn99.com/上下载了sources.list，然后apt-get update时，出现下
面的错误：
Failed to fetch http://debian.cn99.com/debian-non-US/dists/proposed-
updates/non-US/main/binary-i386/Packages.gz 404 Not Found
Failed to fetch http://debian.cn99.com/debian-non-US/dists/proposed-
updates/non-US/contrib/binary-i386/Packages.gz 404 Not Found
Failed to fetch http://debian.cn99.com/debian-non-US/dists/proposed-
updates/non-US/non-free/binary-i386/Packages.gz 404 Not Found
Failed to fetch http://debian.cn99.com/debian-non-US/dists/proposed-
updates/non-US/main/source/Sources.gz 404 Not Found
Failed to fetch http://debian.cn99.com/debian-non-US/dists/proposed-
updates/non-US/contrib/source/Sources.gz 404 Not Found
Failed to fetch http://debian.cn99.com/debian-non-US/dists/proposed-
updates/non-US/non-free/source/Sources.gz 404 Not Found
W: GPG error: http://debian.cn99.com stable Release: Could not
execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: GPG error: http://debian.cn99.com stable/non-US Release: Could not
execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: GPG error: http://debian.cn99.com proposed-updates Release: Could not
execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: GPG error: http://debian.cn99.com woody/updates Release: Could not
execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: Couldn't stat source package list http://debian.cn99.com proposed-
updates/non-US/main Packages (/var/lib/apt/lists/debian.cn99.com_debian-non-
US_dists_proposed-updates_non-US_main_binary-i386_Packages) - stat (2 No
such file or directory)
W: Couldn't stat source package list http://debian.cn99.com proposed-
updates/non-US/contrib Packages (/var/lib/apt/lists/debian.cn99.com_debian-
non-US_dists_proposed-updates_non-US_contrib_binary-i386_Packages) - stat (2
No such file or directory)
W: Couldn't stat source package list http://debian.cn99.com proposed-
updates/non-US/non-free Packages (/var/lib/apt/lists/debian.cn99.com_debian-
non-US_dists_proposed-updates_non-US_non-free_binary-i386_Packages) - stat
(2 No such file or directory)
W: You may want to run apt-get update to correct these problems
E: Some index files failed to download, they have been ignored, or old ones
used instead.

stable和testing都不行，后来还从http://mirrors.geekbone.org/上也下载了
sources.list，也是同样的错误，请问是什么原因呢？

谢谢！

去掉 non-US的内容

我把sources.list改成：

deb http://debian.cn99.com/debian sarge main non-free contrib
deb http://debian.cn99.com/debian testing-proposed-updates main contrib non-free
deb http://debian.cn99.com/debian-security sarge/updates main contrib non-free
deb-src http://debian.cn99.com/debian sarge main non-free contrib
deb-src http://debian.cn99.com/debian testing-proposed-updates main contrib non-free

运行apt-get update时，还是有错误：
W: GPG error: http://debian.cn99.com sarge Release: Could not execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: GPG error: http://debian.cn99.com testing-proposed-updates Release: Could not execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: GPG error: http://debian.cn99.com sarge/updates Release: Could not execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: You may want to run apt-get update to correct these problems

然后我安装gnupg，错误为：
WARNING: The following packages cannot be authenticated!
gnupg
Install these packages without verification [y/N]?

我选择y，然后安装出错：

update-rc.d: /etc/init.d/xfree86-common exists during rc.d purge (use -f to force)
dpkg：处理 xfree86-common (--configure)时出错：
子进程?post-installation script?返回了错误号?1
在处理时有错误发生：
xfree86-common
E: Sub-process /usr/bin/dpkg returned an error code (1)

我是新安装系统，还没有装X

谢谢！

我昨天来了个apt-get dist-upgrade后，今天也出现这个问题了：
#apt-get update
…………
正在读取软件包列表... 完成
W: GPG error: ftp://linux.xjtu.edu.cn etch Release: Could not execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: GPG error: ftp://linux.xjtu.edu.cn etch/updates Release: Could not execute /usr/bin/gpgv to verify signature (is gnupg installed?)
W: 您可能需要运行 apt-get update 来解决这些问题

我接着就执行：
#apt-get install gnupg
安装gnupg的过程中没出现什么问题，
然后再执行apt-get update就没问题了。