I upgraded from Ubuntu 12.04 to Ubuntu 12.10. After this it is not updating . The software updater gives this error:

W:Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/Release.gpg  Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://extras.ubuntu.com/ubuntu/dists/quantal/Release.gpg  Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal/Release.gpg  Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-updates/Release.gpg  Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-backports/Release.gpg Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-security/Release.gpg Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-proposed/Release.gpg Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal/restricted/source/Sources Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal/main/source/Sources  Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal/multiverse/source/Sources Unable to connect to 10.4.42.15:8080:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal/universe/source/Sources Unable to connect to 10.4.42.15:8080:

  :

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/quantal-proposed/universe/i18n/Translation-en Unable to connect to 10.4.42.15:8080:

E:Some index files failed to download. They have been ignored, or old ones used instead.

I am not able to install anything from Software Center; it just asks to use this source and after that it just keeps on querying software sources and nothing happens.

The contents of /etc/apt/sources.list are:

#deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)]/ precise main restricted



# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to

# newer versions of the distribution.

deb http://us.archive.ubuntu.com/ubuntu/ quantal main restricted

deb-src http://us.archive.ubuntu.com/ubuntu/ quantal restricted main multiverse universe #Added by software-properties



## Major bug fix updates produced after the final release of the

## distribution.

deb http://us.archive.ubuntu.com/ubuntu/ quantal-updates main restricted

deb-src http://us.archive.ubuntu.com/ubuntu/ quantal-updates restricted main multiverse universe #Added by software-properties



## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu

## team. Also, please note that software in universe WILL NOT receive any

## review or updates from the Ubuntu security team.

deb http://us.archive.ubuntu.com/ubuntu/ quantal universe

deb http://us.archive.ubuntu.com/ubuntu/ quantal-updates universe



## 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 

## multiverse WILL NOT receive any review or updates from the Ubuntu

## security team.

deb http://us.archive.ubuntu.com/ubuntu/ quantal multiverse

deb http://us.archive.ubuntu.com/ubuntu/ quantal-updates multiverse



## 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 http://us.archive.ubuntu.com/ubuntu/ quantal-backports main restricted universe multiverse

deb-src http://us.archive.ubuntu.com/ubuntu/ quantal-backports main restricted universe multiverse #Added by software-properties



deb http://us.archive.ubuntu.com/ubuntu/ quantal-security main restricted

deb-src http://us.archive.ubuntu.com/ubuntu/ quantal-security restricted main multiverse universe #Added by software-properties

deb http://us.archive.ubuntu.com/ubuntu/ quantal-security universe

deb http://us.archive.ubuntu.com/ubuntu/ quantal-security multiverse



## Uncomment the following two lines to add software from Canonical's

## 'partner' repository.

## This software is not part of Ubuntu, but is offered by Canonical and the

## respective vendors as a service to Ubuntu users.

deb http://archive.canonical.com/ubuntu precise partner

deb-src http://archive.canonical.com/ubuntu precise partner



## This software is not part of Ubuntu, but is offered by third-party

## developers who want to ship their latest software.

deb http://extras.ubuntu.com/ubuntu quantal main

deb-src http://extras.ubuntu.com/ubuntu quantal main

# deb http://download.learnfree.eu/repository/skss / #SKSS

# deb-src http://download.learnfree.eu/repository/skss / #SKSS

deb http://us.archive.ubuntu.com/ubuntu/ quantal-proposed restricted main multiverse universe

deb-src http://us.archive.ubuntu.com/ubuntu/ quantal-proposed restricted main multiverse universe #Added by software-properties