debianp4:~# apt-get update
Get:1 http://debian.fastweb.it etch Release.gpg [189B]
Get:2 http://www.debian-multimedia.org etch Release.gpg [189B]
Hit http://debian.fastweb.it etch Release
Hit http://www.debian-multimedia.org etch Release
Err http://www.debian-multimedia.org etch Release

Hit http://debian.fastweb.it etch/main Packages/DiffIndex
Get:3 http://security.debian.org etch/updates Release.gpg [189B]
Get:4 http://www.debian-multimedia.org etch Release [4868B]
Ign http://www.debian-multimedia.org etch Release
Hit http://debian.fastweb.it etch/contrib Packages/DiffIndex
Hit http://debian.fastweb.it etch/non-free Packages/DiffIndex
Hit http://debian.fastweb.it etch/main Sources/DiffIndex
Hit http://debian.fastweb.it etch/contrib Sources/DiffIndex
Hit http://debian.fastweb.it etch/non-free Sources/DiffIndex
Hit http://security.debian.org etch/updates Release
Ign http://www.debian-multimedia.org etch/main Packages/DiffIndex
Hit http://www.debian-multimedia.org etch/main Packages
Ign http://security.debian.org etch/updates/main Packages/DiffIndex
Ign http://security.debian.org etch/updates/main Sources/DiffIndex
Hit http://security.debian.org etch/updates/main Packages
Hit http://security.debian.org etch/updates/main Sources
Scaricato 5059B in 2s (2308B/s)
Lettura della lista dei pacchetti in corso... Fatto
W: GPG error: http://www.debian-multimedia.org etch Release: Le seguenti firme non sono state verificate perchè la chiave pubblica non è disponibile: NO_PUBKEY 07DC563D1F41B907
W: È consigliabile eseguire apt-get update per correggere questi problemi