This is the error I get when updating Ubuntu:
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.medibuntu.org precise InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2EBC26B60C5A2783 W: Failed to fetch http ://packages.medibuntu.org/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/cooperjona/stormcloud/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found W: Some index files failed to download. They have been ignored, or old ones used instead.
What should I do to resolve this?