should i worry? Get:6 ftp://ftp.nerim.net etch/main Packages [18.8kB] Fetched 21.9kB in 10s (2146B/s) Reading package lists... Done W: GPG error: ftp://ftp.nerim.net etch Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 07DC563D1F41B907 W: You may want to run apt-get update to correct these problems