Got his error after upgrading to Ubuntu 10.10 Maverick Meerkat
W: GPG error: http://extras.ubuntu.com maverick Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY DB141E2302FDF932
The solution is quite simple ;)
sudo apt-key adv –keyserver keyserver.ubuntu.com –recv-keys DB141E2302FDF932
Travelling Linux 