[Debian] Ошибки при обновлении пакетов

W: Duplicate sources.list entry http://security.debian.org/ squeeze/updates/main amd64 Packages (/var/lib/apt/lists/security.debian.org_dists_squeeze_updates_main_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/non-free amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_non-free_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/contrib amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_contrib_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/main amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_main_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/contrib amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_contrib_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/non-free amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_non-free_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/main amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_main_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/non-free amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_non-free_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/contrib amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_contrib_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/main amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_main_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/contrib amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_contrib_binary-amd64_Packages) W: Duplicate sources.list entry http://http.us.debian.org/debian/ squeeze/non-free amd64 Packages (/var/lib/apt/lists/http.us.debian.org_debian_dists_squeeze_non-free_binary-amd64_Packages) W: Вы можете запустить 'apt-get update' для исправления этих ошибок. после выполнении sudo apt-get update ошибка исчезает, но после перезагрузки ошибка вновь появляется.