Attempting to upgrade to Ubuntu version 11.10 using Update Manager fails with error "essential package 'ubuntu-minimal' can not be found anymore"

[Byron Henning]

Full error text:

After your package information was updated the essential package 'ubuntu-minimal' can not be found anymore.
This indicates a serious error, please report this bug using the command 'ubuntu-bug update-manager' in a terminal and include the files in /var/log/dist-upgrade/ in the bug report.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.150.2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Fri Mar 1 09:30:43 2013
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_ZA:en
 LANG=en_ZA.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to natty on 2013-03-01 (0 days ago)

[dino99 (9d9)]

That version is no more maintained