Failed to Fetch error on Precise 12.04 upgrade

[Peter Leopold]

lsb_release -rd
Description: Ubuntu 11.10
Release: 11.10

apt-cache policy pkgname
Evidently, the exact pkgname for the upgrade is unknowable. It is just "the upgrade" to all bits of exposed UI.
(This is itself a bug!)

Error message is
A problem occurred during the update. This is ususally some sort of network problem. Please check the network connection and retry.

Tried twice.

Will try again later.

W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/karmic-backports/main/source/Sources 404 Not Found [IP: 91.189.92.152 80]
, W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/karmic-backports/restricted/source/Sources 404 Not Found [IP: 91.189.92.152 80]
, W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/karmic-backports/universe/source/Sources 404 Not Found [IP: 91.189.92.152 80]
, W:Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/karmic-backports/multiverse/source/Sources 404 Not Found [IP: 91.189.92.152 80]
, E:Some index files failed to download. They have been ignored, or old ones used instead.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[waldo mackay (waldo-bnl)]

It seemed to fail when I was running the update-manager. Now I can neither run the update-manager or synaptic; they both
bugger off after initially showing their windows. This is not good.

[waldo mackay (waldo-bnl)]

I should state that I had previously upgraded to 12.04 from 10.04 and it seems to have been working for a couple of weeks;
however it failed on the last update.

[a_cardoso (apierre-cardoso)]

There are some update about this?
It's affecting me, and at least 3 other people at my company.
We can't do a apt-get update. I've tried change mirrors, remove cache, do pretty much everything I found about the subject.