Updating problems

[polardude1983]

I have a warning sign in my taskbar and when i hit check for updates the following message appears. I have Ubuntu karmic koala


W: GPG error: http://ppa.launchpad.net karmic Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2ED6BB6042C24D89
W: Failed to fetch http://medibuntu.sos-sts.com/repo/dists/karmic/Release.gpg Could not resolve 'medibuntu.sos-sts.com'

W: Failed to fetch http://medibuntu.sos-sts.com/repo/dists/karmic/free/i18n/Translation-en_US.bz2 Could not resolve 'medibuntu.sos-sts.com'

W: Failed to fetch http://medibuntu.sos-sts.com/repo/dists/karmic/non-free/i18n/Translation-en_US.bz2 Could not resolve 'medibuntu.sos-sts.com'

W: Some index files failed to download, they have been ignored, or old ones used instead.

[MelDJ]

try removing medibuntu from software sources then add it back by following the steps from here: https://help.ubuntu.com/community/Medibuntu