I just ran into the same problem. Switching form the country server to the central server seem to have worked around the error message.
#Example of change in sources.list after Synaptic repository changed to "Main server" http://za.archive.ubuntu.com/ubuntu/ ->> http://archive.ubuntu.com/ubuntu/
#Error before: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <email address hidden>
$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 9.10 Release: 9.10 Codename: karmic
Not a ideal situation.
I just ran into the same problem.
Switching form the country server to the central server seem to have worked around the error message.
#Example of change in sources.list after Synaptic repository changed to "Main server" za.archive. ubuntu. com/ubuntu/ ->> http:// archive. ubuntu. com/ubuntu/
http://
#Error before:
The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <email address hidden>
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 9.10
Release: 9.10
Codename: karmic
Not a ideal situation.