Ubuntu GPG Error
If you come across this error after running aptitude update or clicking reload button in Synaptic: W: GPG error: http://ppa.launchpad.net intrepid Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 58403026387EE263 W: You may want to run apt-get update to correct these problems due to a missing GPG key…