Comment 2 for bug 326409

Hi! I had exactly the same error while updating packages (via synaptic or update manager), Under Ubuntu 8.10 (32 bit).

I found a solution here: http://my-it-dump.blogspot.com/2009/02/fixing-gpg-errors-nopubkey-in-apt-get.html

So follow this article and this will fix the problem! It worked for me.