Если вы получаете только ошибки, связанные с packages.medibuntu.org, этот репозиторий закрыт в соответствии с официальной страницей репо на панели запуска и этими темами обсуждения.
W: Failed to fetch http://packages.medibuntu.org/dists/precise/Release.gpg Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/free/source/Sources Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/non-free/source/Sources Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/free/binary-amd64/Packages Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/non-free/binary-amd64/Packages Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/free/binary-i386/Packages Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/non-free/binary-i386/Packages Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/free/i18n/Translation-en_US Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/free/i18n/Translation-en Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/non-free/i18n/Translation-en_US Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
W: Failed to fetch http://packages.medibuntu.org/dists/precise/non-free/i18n/Translation-en Something wicked happened resolving 'packages.medibuntu.org:http' (-5 - No address associated with hostname)
E: Some index files failed to download. They have been ignored, or old ones used instead.
[d6 ] Решение: