Couldn't update to 9.10: ubuntu-minimal missing

[ting.]

Binary package hint: update-manager

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 against the 'update-manager' package and include the files in /var/log/dist-upgrade/ in the bug report.

--------

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
NonfreeKernelModules: nvidia
Package: update-manager 1:0.111.9
PackageArchitecture: all
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Uname: Linux 2.6.28-16-generic i686

[ting. (constantine)]

ting@ubuntu:~$ apt-cache policy ubuntu-minimal
ubuntu-minimal:
  Installed: 1.140
  Candidate: 1.140
  Version table:
 *** 1.140 0
        500 http://us.archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/status