Você pode tentar desativar as entradas em /etc/apt/sources.list.d que correspondem a lucid-bleed , pois são elas que estão dando erros.
Não consigo instalar nenhum software no meu sistema Ubuntu 12.04 LTS.
Aqui está a saída de sudo apt-get update
Ign http://dl.google.com stable InRelease
Ign http://dl.google.com stable InRelease
Hit http://dl.google.com stable Release.gpg
Ign http://archive.canonical.com precise InRelease
Ign http://ppa.launchpad.net precise InRelease
Ign http://ppa.launchpad.net precise InRelease
Ign http://ppa.launchpad.net precise InRelease
Hit http://dl.google.com stable Release.gpg
Hit http://archive.canonical.com precise Release.gpg
Hit http://dl.google.com stable Release
Hit http://dl.google.com stable Release
Ign http://ppa.launchpad.net precise InRelease
Ign http://ppa.launchpad.net precise InRelease
Ign http://ppa.launchpad.net precise Release.gpg
Hit http://archive.canonical.com precise Release
Hit http://dl.google.com stable/main amd64 Packages
Hit http://dl.google.com stable/main i386 Packages
Ign http://archive.ubuntu.com precise InRelease
Ign http://archive.ubuntu.com precise-updates InRelease
Ign http://archive.ubuntu.com precise-backports InRelease
Ign http://security.ubuntu.com precise-security InRelease
Ign http://dl.google.com stable/main TranslationIndex
Hit http://ppa.launchpad.net precise Release.gpg
Hit http://ppa.launchpad.net precise Release.gpg
Hit http://ppa.launchpad.net precise Release.gpg
Hit http://archive.canonical.com precise/partner amd64 Packages
Hit http://dl.google.com stable/main amd64 Packages
Ign http://extras.ubuntu.com precise InRelease
Hit http://dl.google.com stable/main i386 Packages
Hit http://archive.ubuntu.com precise Release.gpg
Hit http://archive.ubuntu.com precise-updates Release.gpg
Ign http://dl.google.com stable/main TranslationIndex
Hit http://security.ubuntu.com precise-security Release.gpg
Hit http://archive.canonical.com precise/partner i386 Packages
Ign http://archive.canonical.com precise/partner TranslationIndex
Hit http://ppa.launchpad.net precise Release.gpg
Hit http://extras.ubuntu.com precise Release.gpg
Hit http://archive.ubuntu.com precise-backports Release.gpg
Hit http://archive.ubuntu.com precise Release
Hit http://security.ubuntu.com precise-security Release
Ign http://ppa.launchpad.net precise Release
Hit http://ppa.launchpad.net precise Release
Hit http://ppa.launchpad.net precise Release
Hit http://archive.ubuntu.com precise-updates Release
Hit http://archive.ubuntu.com precise-backports Release
Hit http://extras.ubuntu.com precise Release
Hit http://ppa.launchpad.net precise Release
Hit http://security.ubuntu.com precise-security/main amd64 Packages
Hit http://archive.ubuntu.com precise/main amd64 Packages
Hit http://archive.ubuntu.com precise/restricted amd64 Packages
Hit http://archive.ubuntu.com precise/universe amd64 Packages
Hit http://archive.ubuntu.com precise/multiverse amd64 Packages
Hit http://archive.ubuntu.com precise/main i386 Packages
Hit http://archive.ubuntu.com precise/restricted i386 Packages
Hit http://archive.ubuntu.com precise/universe i386 Packages
Hit http://ppa.launchpad.net precise Release
Ign http://ppa.launchpad.net precise/main TranslationIndex
Hit http://security.ubuntu.com precise-security/restricted amd64 Packages
Hit http://security.ubuntu.com precise-security/universe amd64 Packages
Hit http://security.ubuntu.com precise-security/multiverse amd64 Packages
Hit http://security.ubuntu.com precise-security/main i386 Packages
Hit http://security.ubuntu.com precise-security/restricted i386 Packages
Hit http://security.ubuntu.com precise-security/universe i386 Packages
Hit http://security.ubuntu.com precise-security/multiverse i386 Packages
Hit http://security.ubuntu.com precise-security/main TranslationIndex
Hit http://security.ubuntu.com precise-security/multiverse TranslationIndex
Hit http://security.ubuntu.com precise-security/restricted TranslationIndex
Hit http://extras.ubuntu.com precise/main amd64 Packages
Hit http://archive.ubuntu.com precise/multiverse i386 Packages
Hit http://archive.ubuntu.com precise/main TranslationIndex
Hit http://archive.ubuntu.com precise/multiverse TranslationIndex
Hit http://archive.ubuntu.com precise/restricted TranslationIndex
Hit http://archive.ubuntu.com precise/universe TranslationIndex
Hit http://archive.ubuntu.com precise-updates/main amd64 Packages
Hit http://archive.ubuntu.com precise-updates/restricted amd64 Packages
Hit http://archive.ubuntu.com precise-updates/universe amd64 Packages
Hit http://ppa.launchpad.net precise/main Sources
Hit http://ppa.launchpad.net precise/main amd64 Packages
Hit http://ppa.launchpad.net precise/main i386 Packages
Ign http://ppa.launchpad.net precise/main TranslationIndex
Hit http://ppa.launchpad.net precise/main Sources
Hit http://security.ubuntu.com precise-security/universe TranslationIndex
Hit http://extras.ubuntu.com precise/main i386 Packages
Ign http://extras.ubuntu.com precise/main TranslationIndex
Ign http://dl.google.com stable/main Translation-en_US
Hit http://archive.ubuntu.com precise-updates/multiverse amd64 Packages
Hit http://archive.ubuntu.com precise-updates/main i386 Packages
Hit http://archive.ubuntu.com precise-updates/restricted i386 Packages
Hit http://archive.ubuntu.com precise-updates/universe i386 Packages
Hit http://archive.ubuntu.com precise-updates/multiverse i386 Packages
Hit http://archive.ubuntu.com precise-updates/main TranslationIndex
Hit http://archive.ubuntu.com precise-updates/multiverse TranslationIndex
Hit http://archive.ubuntu.com precise-updates/restricted TranslationIndex
Hit http://ppa.launchpad.net precise/main amd64 Packages
Hit http://ppa.launchpad.net precise/main i386 Packages
Ign http://ppa.launchpad.net precise/main TranslationIndex
Hit http://ppa.launchpad.net precise/main Sources
Hit http://ppa.launchpad.net precise/main amd64 Packages
Ign http://dl.google.com stable/main Translation-en
Hit http://security.ubuntu.com precise-security/main Translation-en
Hit http://security.ubuntu.com precise-security/multiverse Translation-en
Ign http://dl.google.com stable/main Translation-en_US
Ign http://dl.google.com stable/main Translation-en
Hit http://archive.ubuntu.com precise-updates/universe TranslationIndex
Hit http://archive.ubuntu.com precise-backports/main amd64 Packages
Hit http://archive.ubuntu.com precise-backports/restricted amd64 Packages
Hit http://archive.ubuntu.com precise-backports/universe amd64 Packages
Hit http://archive.ubuntu.com precise-backports/multiverse amd64 Packages
Hit http://archive.ubuntu.com precise-backports/main i386 Packages
Hit http://ppa.launchpad.net precise/main i386 Packages
Hit http://archive.ubuntu.com precise-backports/restricted i386 Packages
Ign http://ppa.launchpad.net precise/main TranslationIndex
Hit http://security.ubuntu.com precise-security/restricted Translation-en
Hit http://archive.ubuntu.com precise-backports/universe i386 Packages
Hit http://archive.ubuntu.com precise-backports/multiverse i386 Packages
Hit http://archive.ubuntu.com precise-backports/main TranslationIndex
Hit http://archive.ubuntu.com precise-backports/multiverse TranslationIndex
Hit http://archive.ubuntu.com precise-backports/restricted TranslationIndex
Hit http://archive.ubuntu.com precise-backports/universe TranslationIndex
Hit http://archive.ubuntu.com precise/main Translation-en
Hit http://archive.ubuntu.com precise/multiverse Translation-en
Hit http://ppa.launchpad.net precise/main Sources
Hit http://ppa.launchpad.net precise/main amd64 Packages
Hit http://ppa.launchpad.net precise/main i386 Packages
Ign http://archive.canonical.com precise/partner Translation-en_US
Hit http://security.ubuntu.com precise-security/universe Translation-en
Ign http://archive.canonical.com precise/partner Translation-en
Hit http://archive.ubuntu.com precise/restricted Translation-en
Hit http://archive.ubuntu.com precise/universe Translation-en
Hit http://archive.ubuntu.com precise-updates/main Translation-en
Hit http://archive.ubuntu.com precise-updates/multiverse Translation-en
Hit http://archive.ubuntu.com precise-updates/restricted Translation-en
Ign http://ppa.launchpad.net precise/main TranslationIndex
Hit http://archive.ubuntu.com precise-updates/universe Translation-en
Hit http://archive.ubuntu.com precise-backports/main Translation-en
Hit http://archive.ubuntu.com precise-backports/multiverse Translation-en
Hit http://archive.ubuntu.com precise-backports/restricted Translation-en
Hit http://archive.ubuntu.com precise-backports/universe Translation-en
Err http://ppa.launchpad.net precise/main Sources
404 Not Found
Err http://ppa.launchpad.net precise/main amd64 Packages
404 Not Found
Err http://ppa.launchpad.net precise/main i386 Packages
404 Not Found
Ign http://extras.ubuntu.com precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en
Ign http://extras.ubuntu.com precise/main Translation-en
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en
W: Failed to fetch http://ppa.launchpad.net/lucid-bleed/ppa/ubuntu/dists/precise/main/source/Sources 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/lucid-bleed/ppa/ubuntu/dists/precise/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/lucid-bleed/ppa/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
Você pode tentar desativar as entradas em /etc/apt/sources.list.d que correspondem a lucid-bleed , pois são elas que estão dando erros.