Estou usando o Ubuntu 11.10 de 64 bits. Quando tento executar sudo apt-get update . O seguinte lança no terminal:
Hit http://archive.ubuntu.com oneiric-updates/restricted i386 Packages
Hit http://archive.ubuntu.com oneiric-updates/universe i386 Packages
Hit http://archive.ubuntu.com oneiric-updates/multiverse i386 Packages
Hit http://security.ubuntu.com oneiric-security/restricted Translation-en
Ign http://ppa.launchpad.net oneiric/main TranslationIndex
Hit http://toolbelt.heroku.com ./ Release
Ign http://extras.ubuntu.com oneiric/main TranslationIndex
Hit http://archive.ubuntu.com oneiric-updates/main TranslationIndex
Hit http://archive.ubuntu.com oneiric-updates/multiverse TranslationIndex
Hit http://archive.ubuntu.com oneiric-updates/restricted TranslationIndex
Hit http://archive.ubuntu.com oneiric-updates/universe TranslationIndex
Hit http://archive.ubuntu.com oneiric-backports/main amd64 Packages
Hit http://archive.ubuntu.com oneiric-backports/restricted amd64 Packages
Hit http://archive.ubuntu.com oneiric-backports/universe amd64 Packages
Hit http://security.ubuntu.com oneiric-security/universe Translation-en
Hit http://ppa.launchpad.net oneiric/main Sources
Hit http://ppa.launchpad.net oneiric/main amd64 Packages
Hit http://ppa.launchpad.net oneiric/main i386 Packages
Ign http://ppa.launchpad.net oneiric/main TranslationIndex
Hit http://archive.ubuntu.com oneiric-backports/multiverse amd64 Packages
Hit http://archive.ubuntu.com oneiric-backports/main i386 Packages
Hit http://archive.ubuntu.com oneiric-backports/restricted i386 Packages
Hit http://archive.ubuntu.com oneiric-backports/universe i386 Packages
Hit http://archive.ubuntu.com oneiric-backports/multiverse i386 Packages
Hit http://archive.ubuntu.com oneiric-backports/main TranslationIndex
Hit http://archive.ubuntu.com oneiric-backports/multiverse TranslationIndex
Hit http://archive.ubuntu.com oneiric-backports/restricted TranslationIndex
Hit http://archive.ubuntu.com oneiric-backports/universe TranslationIndex
Hit http://archive.ubuntu.com oneiric/main Translation-en
Hit http://archive.ubuntu.com oneiric/multiverse Translation-en
Hit http://archive.ubuntu.com oneiric/restricted Translation-en
Hit http://archive.ubuntu.com oneiric/universe Translation-en
Hit http://archive.ubuntu.com oneiric-updates/main Translation-en
Hit http://archive.ubuntu.com oneiric-updates/multiverse Translation-en
Hit http://archive.ubuntu.com oneiric-updates/restricted Translation-en
Hit http://archive.ubuntu.com oneiric-updates/universe Translation-en
Hit http://archive.ubuntu.com oneiric-backports/main Translation-en
Hit http://archive.ubuntu.com oneiric-backports/multiverse Translation-en
Hit http://archive.ubuntu.com oneiric-backports/restricted Translation-en
Hit http://archive.ubuntu.com oneiric-backports/universe Translation-en
Hit http://toolbelt.heroku.com ./ Packages
Ign http://deb.opera.com stable/non-free Translation-en_US
Ign http://deb.opera.com stable/non-free Translation-en
Ign http://archive.canonical.com oneiric/partner Translation-en_US
Ign http://linux.dropbox.com oneiric/main Translation-en_US
Err http://ppa.launchpad.net oneiric/main Sources
404 Not Found
Err http://ppa.launchpad.net oneiric/main amd64 Packages
404 Not Found
Ign http://archive.canonical.com oneiric/partner Translation-en
Ign http://archive.canonical.com oneiric/partner Translation-en_US
Ign http://linux.dropbox.com oneiric/main Translation-en
Err http://ppa.launchpad.net oneiric/main i386 Packages
404 Not Found
Ign http://archive.canonical.com oneiric/partner Translation-en
Ign http://dell.archive.canonical.com oneiric-dell/public Translation-en_US
Ign http://extras.ubuntu.com oneiric/main Translation-en_US
Ign http://dell.archive.canonical.com oneiric-dell/public Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en_US
Ign http://extras.ubuntu.com oneiric/main Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en_US
Ign http://ppa.launchpad.net oneiric/main Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en_US
Ign http://ppa.launchpad.net oneiric/main Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en_US
Ign http://ppa.launchpad.net oneiric/main Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en_US
Ign http://ppa.launchpad.net oneiric/main Translation-en
Ign http://ppa.launchpad.net oneiric/main Translation-en_US
Ign http://ppa.launchpad.net oneiric/main Translation-en
Ign http://toolbelt.heroku.com ./ Translation-en_US
Ign http://toolbelt.heroku.com ./ Translation-en
W: Failed to fetch http://ppa.launchpad.net/ferramroberto/filezilla/ubuntu/dists/oneiric/main/source/Sources 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/ferramroberto/filezilla/ubuntu/dists/oneiric/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/ferramroberto/filezilla/ubuntu/dists/oneiric/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
Isso porque 11,10 alcançou a EOL e não é mais suportado. Eu recomendaria que você atualize para pelo menos 12.04. Mas se o seu sistema é capaz , você pode querer instalar o 13.04.
Se decidir atualizar, recomendo que você faça uma nova instalação. Certifique-se de fazer backup de todos os seus dados. Caso contrário, você tem que fazer 11.10 - > 12,04 - > 12,10 - > 13,04