Repository problem in Kubuntu.

I had problems with the repositories. I was unable to update the installed packaged or install any new packages. The software manager Adept would fail and apt-get would return various errors when trying to connect to the repositories. I was able to ping the repositories which made the situation even more curious. I am not sure what the problem is. I even tried reinstalling. The default repositories were still unavailable.

I was finally able to get access to the repositories by using the FTP versions of the Canadian Ubuntu repositories. The repositories that worked for me are given below.

# deb http://archive.canonical.com/ubuntu dapper-commercial main
# deb ftp://bolugftp.uni-bonn.de/pub/kde/stable/3.5.4/kubuntu dapper main
# deb http://www.mirrorservice.org/sites/ftp.kde.org/pub/kde/stable/3.5.4/kubuntu dapper main
# deb http://mirror.cc.columbia.edu/pub/software/kde/stable/3.5.4/kubuntu dapper main

# Line commented out by installer because it failed to verify:
deb ftp://ca.archive.ubuntu.com/ubuntu/ dapper main restricted
deb ftp://ca.archive.ubuntu.com/ubuntu/ dapper multiverse
# Line commented out by installer because it failed to verify:
# deb-src http://us.archive.ubuntu.com/ubuntu/ dapper main restricted

## Major bug fix updates produced after the final release of the
## distribution.
# Line commented out by installer because it failed to verify:
deb ftp://ca.archive.ubuntu.com/ubuntu/ dapper-updates main restricted
# Line commented out by installer because it failed to verify:
# deb-src http://us.archive.ubuntu.com/ubuntu/ dapper-updates main restricted

## Uncomment the following two lines to add software from the 'universe'
## repository.
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb ftp://ca.archive.ubuntu.com/ubuntu/ dapper universe
# deb-src http://us.archive.ubuntu.com/ubuntu/ dapper universe

## Uncomment the following two lines to add software from the 'backports'
## repository.
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb ftp://ca.archive.ubuntu.com/ubuntu/ dapper-backports main restricted universe multiverse

# Line commented out by installer because it failed to verify:
# deb http://security.ubuntu.com/ubuntu dapper-security main
# Line commented out by installer because it failed to verify:
# deb-src http://security.ubuntu.com/ubuntu dapper-security main
# deb-src http://us.archive.ubuntu.com/ubuntu/ dapper-backports main restricted universe multiverse
# deb ftp://security.ubuntu.com/ubuntu dapper-security universe
# deb-src http://security.ubuntu.com/ubuntu dapper-security universe



linux,repository,ubuntu,kubuntu