Problema con el gestor de paquetes Synaptic

[gambill]

Esto es lo que contiene(he sustituido los puntos y las barras / por guiones bajos _ para superar el filtro anti spam,ya que no me dejan colgar direcciones web hasta que no tenga más de 30 días de antiguedad o más de 30 mensajes publicados.Perdonad las molestias):

cat /etc/apt/sources.list
# See http_help_ubuntu_com_community_UpgradeNotes for how to upgrade to
# newer versions of the distribution.

deb http_es_archiveubuntu_com_ubuntu_ feisty main restricted
deb-src http_es_archive_ubuntu_com_ubuntu_ feisty main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http_es_archive_ubuntu_com_ubuntu_ feisty-updates main restricted
deb-src http_es_archive_ubuntu_com_ubuntu_ feisty-updates main restricted

## 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 http_es_archive_ubuntu_com_ubuntu_ feisty universe
deb-src http_es_archive_ubuntu_com_ubuntu_ feisty 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_es_archive_ubuntu_com_ubuntu_ feisty multiverse
deb-src http_es_archive_ubuntu_com_ubuntu_ feisty multiverse

## 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 http_es_archive_ubuntu_com_ubuntu_ feisty-backports main restricted universe multiverse
# deb-src http_es_archive_ubuntu_com_ubuntu_ feisty-backports main restricted universe multiverse

deb http_security_ubuntu_com_ubuntu feisty-security main restricted
deb-src http_security_ubuntu_com_ubuntu feisty-security main restricted
deb http_security_ubuntu_com_ubuntu feisty-security universe
deb-src http_security_ubuntu_com_ubuntu feisty-security universe
deb http_security_ubuntu_com_ubuntu feisty-security multiverse
deb-src http_security_ubuntu_com_ubuntu feisty-security multiverse