W: GPG error: ftp://ftp.nerim.net stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 07DC563D1F41B907
W: GPG error: ftp://ftp.nerim.net unstable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 07DC563D1F41B907
W: GPG error: ftp://ftp.nerim.net testing Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 07DC563D1F41B907
W: È consigliabile eseguire apt-get update per correggere questi problemi