debian:/home/juan# gedit /etc/apt/sources.list

(gedit:4656): GnomeUI-WARNING **: While connecting to session manager:
Authentication Rejected, reason : None of the authentication protocols specified  are supported and host-based authentication failed.
debian:/home/juan# apt-get update
Des:1 http://http.us.debian.org etch Release.gpg [189B]
Des:2 http://security.debian.org etch/updates Release.gpg [189B]
Des:3 http://security.debian.org testing/updates Release.gpg [189B]
Obj http://http.us.debian.org etch Release
Obj http://security.debian.org etch/updates Release
Obj http://http.us.debian.org etch/main Packages/DiffIndex
Des:4 http://security.debian.org testing/updates Release [24,3kB]
Des:5 http://www.debian-multimedia.org etch Release.gpg [189B]
Des:6 http://www.debian-multimedia.org etch Release [5560B]
Ign http://security.debian.org etch/updates/main Packages/DiffIndex
Ign http://security.debian.org etch/updates/contrib Packages/DiffIndex
Ign http://security.debian.org etch/updates/main Sources/DiffIndex
Ign http://security.debian.org etch/updates/contrib Sources/DiffIndex
Ign http://www.debian-multimedia.org etch Release
Obj http://http.us.debian.org etch/contrib Packages/DiffIndex
Des:7 http://security.debian.org testing/updates/main Packages [5327B]
Obj http://security.debian.org etch/updates/main Packages
Obj http://http.us.debian.org etch/non-free Packages/DiffIndex
Obj http://security.debian.org etch/updates/contrib Packages
Obj http://security.debian.org etch/updates/main Sources
Obj http://security.debian.org etch/updates/contrib Sources
Des:8 http://www.debian-multimedia.org etch/main Packages [43,9kB]
Descargados 79,5kB en 7s (10,2kB/s)
Leyendo lista de paquetes... Hecho
W: GPG error: http://www.debian-multimedia.org etch Release: Las firmas siguient es no se pudieron verificar porque su llave pública no está disponible: NO_PUBKE Y 07DC563D1F41B907
W: Tal vez quiera ejecutar 'apt-get update' para corregir estos problemas
debian:/home/juan#