GPG error: How to fix it?

[fantab]

I wanted to update Oneiric Ocelot_64 today and I get the following GPG ERROR:

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

W: GPG error: http://in.archive.ubuntu.com oneiric Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://in.archive.ubuntu.com oneiric-updates Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://in.archive.ubuntu.com oneiric-backports Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/oneiric/Release

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

Please HELP me FIX this.

Thanks.

[fantab]

Ok... I fixed it.

$ sudo -i
 # apt-get clean
 # cd /var/lib/apt
 # mv lists lists.old
 # mkdir -p lists/partial
 # apt-get clean
 # apt-get update

[GadsdenMedia]

Thanks Fantab - I'm dealing with the worst upgrade with Ubuntu I've ever had, and I think your post helped me clear up the last of the issues.

Now to update the remaining 500 or so packages that for some reason didn't get installed with I did the dist-upgrade.

[talking Llama]

THANK YOU! I've had this problem for a while now and this fixed it nicely. Thanks very much!