apt-get update遇到的问题

我在更新安装源的时候遇到如下信息，我应该怎么办才能把那些错误的和忽略的改正过来？AAA:/home/alan# apt-get update
命中 http://debian.cn99.com stable/main Packages
命中 http://debian.cn99.com stable/main Release
命中 http://debian.cn99.com stable/main Sources
命中 http://debian.cn99.com stable/main Release
错误 http://debian.okey.net main/non-free Packages
404 Not Found
忽略 http://debian.okey.net main/non-free Release
错误 http://debian.okey.net main/contrib Packages
404 Not Found
忽略 http://debian.okey.net main/contrib Release
命中 http://debian.okey.net unstable/firefly Packages
命中 http://debian.okey.net unstable/firefly Release
命中 http://debian.okey.net unstable/java Packages
命中 http://debian.okey.net unstable/java Release
命中 http://debian.okey.net unstable/jrfonseca Packages
忽略 http://debian.okey.net unstable/jrfonseca Release
命中 http://debian.okey.net unstable/marillat Packages
命中 http://debian.okey.net unstable/marillat Release
命中 http://debian.okey.net unstable/misc Packages
命中 http://debian.okey.net unstable/misc Release
命中 http://debian.okey.net unstable/rareware Packages
命中 http://debian.okey.net unstable/rareware Release
命中 http://debian.okey.net unstable/ustc Packages
命中 http://debian.okey.net unstable/ustc Release
命中 http://security.debian.org stable/updates/main Packages
命中 http://security.debian.org stable/updates/main Release
获取：1 ftp://ftp.nerim.net unstable/main Packages
错误 ftp://ftp.nerim.net unstable/main Packages
无法获取文件，服务器响应道“Can't open /debian-marillat/dists/unstable/main/binary-i386/Packages.gz: No such file or directory ”
获取：2 ftp://ftp.nerim.net unstable/main Release
忽略 ftp://ftp.nerim.net unstable/main Release
获取：3 ftp://ftp.nerim.net unstable/main Sources
错误 ftp://ftp.nerim.net unstable/main Sources
无法获取文件，服务器响应道“Can't open /debian-marillat/dists/unstable/main/source/Sources.gz: No such file or directory ”
获取：4 ftp://ftp.nerim.net unstable/main Release
忽略 ftp://ftp.nerim.net unstable/main Release
无法下载 ftp://ftp.nerim.net/debian-marillat/...86/Packages.gz 无法获取文件，服务器响应道“Can't open /debian-marillat/dists/unstable/main/binary-i386/Packages.gz: No such file or directory ”
无法下载 ftp://ftp.nerim.net/debian-marillat/...rce/Sources.gz 无法获取文件，服务器响应道“Can't open /debian-marillat/dists/unstable/main/source/Sources.gz: No such file or directory ”
无法下载 http://debian.okey.net/debian/sarge/...86/Packages.gz 404 Not Found
无法下载 http://debian.okey.net/debian/sarge/...86/Packages.gz 404 Not Found
E: 无法获得锁 /var/lib/dpkg/lock - open (11 资源暂时不可用)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?
AAA:/home/alan#

这个是经常碰到的情况吧

我觉得应该是源的问题，搭车同问~~~