---

Saludos. Fijense que cuando trato de ejecutar sudo apt-get update en mi equipo Ubuntu, me da los siguientes errores:

Err http://ca.archive.ubuntu.com gutsy-updates/restricted Sources
404 Not Found [IP: 91.189.88.140 80]
Err http://ca.archive.ubuntu.com gutsy-updates/universe Packages
404 Not Found [IP: 91.189.88.140 80]
Err http://ca.archive.ubuntu.com gutsy-updates/universe Sources
404 Not Found [IP: 91.189.88.140 80]
Err http://ca.archive.ubuntu.com gutsy-updates/multiverse Packages
404 Not Found [IP: 91.189.88.140 80]
Err http://ca.archive.ubuntu.com gutsy-updates/multiverse Sources
404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy/multiverse/binary-i386/Packages.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy/multiverse/source/Sources.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/main/binary-i386/Packages.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/restricted/binary-i386/Packages.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/main/source/Sources.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/restricted/source/Sources.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/universe/binary-i386/Packages.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/universe/source/Sources.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/multiverse/binary-i386/Packages.gz 404 Not Found [IP: 91.189.88.140 80]
Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/gutsy-updates/multiverse/source/Sources.gz 404 Not Found [IP: 91.189.88.140 80]
Reading package lists... Done
E: Some index files failed to download, they have been ignored, or old ones used instead.

¿Saben a que se deba esto?. Intento actualizar a razon de que necesito instalar el servicio IMAP de PHP mediante sudo apt-get install php5-imap, sin embargo me da un resultado similar.

Espero alguien pueda orientarme. Desde ya muchas gracias 

---

Creo que es que no tienes internet, el error que te da es que no puede conectarse con los repositorios, porque no encuentra las ips o porque la direccion del repositorio son erroneas y ya no existen,