Помогите, пожалуйста. такая херня жму в терминале sudo apt-get update. Он вроде обновляет, но под конец вылазит такая херня


Reading package lists... Done
W: GPG error: /security.ubuntu.com precise-security Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: /extras.ubuntu.com precise Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key

W: GPG error: /archive.canonical.com precise Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key
W: GPG error: /ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG 3BDAAC08614C4B38 Launchpad otto06217
W: GPG error: /ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG 6AF0E1940624A220 Launchpad PPA for TualatriX
W: GPG error: /ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG 5A9A06AEF9CB8DB0 Launchpad PPA for Ubuntu Wine Team
W: GPG error: /ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG A5D712AEE06E6293 Launchpad PPA for upubuntu.com
W: GPG error: /ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG A5D712AEE06E6293 Launchpad PPA for upubuntu.com
W: Failed to fetch /extras.ubuntu.com/ubuntu/dists/precise/Release

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


То есть, как я понял, он не обновился. Похожая херня творится с менеджером обновлений. Подскажите, пожалуйста, что делать с этим, заранее спасибо.