Probleme de mise à jour

Bonjour,
je sui sur ubuntu 10.04 et quand j'essaye d'installer les mise à jours disponibles suggérer par le gestionnaire de mise à jour; je trouve ce mlessage :

W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid/main Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid_main_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid/restricted Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid/main Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid_main_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid/restricted Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid-updates/main Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid-updates_main_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid-updates/restricted Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid-updates_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid-updates/main Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid-updates_main_binary-i386_Packages)
W: Duplicate sources.list entry http://fr.archive.ubuntu.com/ubuntu/ lucid-updates/restricted Packages (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_lucid-updates_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/main Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/main Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/main Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/main Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/main Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/main Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)

j'attent vos remèdes, merci d'avance ;)