우분투 apt-get... 할때 오류

우분투를 새로 깔고 package를 여럿 설치하고 있는데요.
계속 에러나면서 --fix-missing 옵션을 써보라고 나옵니다. 이런 원인을 알수 있을까요?
새로깔기전에는 잘 됐었거든요.

아래는 apt-file을 설치하는 중에 생기는 문제있는 다른 package 설치시에도 이렇게 문제가 되는게 많습니다.
그래서 --fix-missing 옵션을 쓰면 될때도 있고 안될때도 있구요,,

xxx@xxx-ubuntu:~/eclipse$ sudo apt-get install apt-file
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
texlive-pictures-doc texlive-pstricks-doc lmodern texlive-common texlive-latex-extra-doc
preview-latex-style texlive-latex-recommended-doc texlive-latex-base-doc ps2eps tex-common
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
curl libapt-pkg-perl libconfig-file-perl libcurl3 liblist-moreutils-perl libregexp-assemble-perl
The following NEW packages will be installed
apt-file curl libapt-pkg-perl libconfig-file-perl libcurl3 liblist-moreutils-perl
libregexp-assemble-perl
0 upgraded, 7 newly installed, 0 to remove and 207 not upgraded.
Need to get 408 kB/643 kB of archives.
After this operation, 2,142 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://kr.archive.ubuntu.com/ubuntu/ oneiric/main curl i386 7.21.6-3ubuntu3 [134 kB]
Get:2 http://kr.archive.ubuntu.com/ubuntu/ oneiric/universe libconfig-file-perl all 1.50-2 [10.1 kB]
Get:3 http://kr.archive.ubuntu.com/ubuntu/ oneiric/main libapt-pkg-perl i386 0.1.24build3 [89.6 kB]
Get:4 http://kr.archive.ubuntu.com/ubuntu/ oneiric/main liblist-moreutils-perl i386 0.32-1 [59.5 kB]
Get:5 http://kr.archive.ubuntu.com/ubuntu/ oneiric/universe libregexp-assemble-perl all 0.34-6 [89.3 kB]
Get:6 http://kr.archive.ubuntu.com/ubuntu/ oneiric/universe apt-file all 2.5.0ubuntu1 [25.6 kB]
Fetched 357 kB in 1min 1s (5,825 B/s)
Failed to fetch http://kr.archive.ubuntu.com/ubuntu/pool/main/c/curl/curl_7.21.6-3ubuntu3_i386.deb Hash Sum mismatch
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?