Packages don't download to update from ubuntu 11.10 to 12.04. Tried via update manager & via terminal command

[Tim Miller]

I tried to update to ubuntu 12.04 a few times via update manager & it said downloading package 1 of 2. Then just disappears & gives no indication its finished or still going. Found out how to check my version of Ubuntu & its still 11.10. Tried updating via terminal got this msg.

Err Upgrade tool [5612 kb]
Fetched 5612 kB in 6s (895 kB/s)
WARNING:root:file 'precise.tar.gz.gpg' missing
Failed to fetch
Fetching the upgrade failed. There may be a network problem.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: update-manager 1:0.152.25.11
ProcVersionSignature: Ubuntu 3.0.0-20.34-generic 3.0.30
Uname: Linux 3.0.0-20-generic i686
ApportVersion: 1.23-0ubuntu4
Architecture: i386
Date: Sun May 27 11:47:33 2012
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_NZ.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to oneiric on 2011-10-16 (223 days ago)

[dino99 (9d9)]

This version has expired