Essa mensagem aparece quando mando checar o respositório: "Failed to download repository information".
Os detalhes:
W:GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2EA8F35793D8809A, W:Failed to fetch http://ppa.launchpad.net/sun-java-community-team/sun-java6/ubuntu/dists/precise/main/source/Sources 404 Not Found
, W:Failed to fetch http://ppa.launchpad.net/sun-java-community-team/sun-java6/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found
, E:Some index files failed to download. They have been ignored, or old ones used instead.
Como resolver isso?