There is no public key available for the following key ID
Monday, May 25th, 2009$ gpg –keyserver wwwkeys.eu.pgp.net –recv-keys 4D270D06F42584E6
# You should see the following output while executing the above command.
gpg: Total number processed: 1
gpg: imported: 1
$ gpg –armor –export 4D270D06F42584E6 | apt-key add -
OK
$ apt-get update
[Note: Now update will work without the key error message]