Failed to download repository information

[BarryD9545]

I recently upgraded to 12.10 (past three weeks) and got the titled error message today for the first time.
The detailed information:

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/natty-backports/main/source/Sources 404 Not Found [IP: 91.189.91.15 80]
, W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/natty-backports/restricted/source/Sources 404 Not Found [IP: 91.189.91.15 80]
, W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/natty-backports/universe/source/Sources 404 Not Found [IP: 91.189.91.15 80]
, W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/natty-backports/multiverse/source/Sources 404 Not Found [IP: 91.189.91.15 80]
, E:Some index files failed to download. They have been ignored, or old ones used instead.

Any help is much appreciated.

Thanks!

[nipunshakya]

The following might help:

http://ubuntuforums.org/showthread.php?t=1654068

Happy Linuxing