I'm using Ubuntu 12.04 LTS 64 bit on a Pacard Bell dot S netbook with intel atom 64 bit processor.
I get then following message when using either apt-get update or upgrade. Upgrade stops on this but update carries out the updates then reports the error
W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ precise/partner amd64 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_precise_partner_binary-amd64_Packages)
W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ precise/partner i386 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_precise_partner_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems
If I remove the files when I run upgrade or update they recur.