Bug#650841: update-manager: package informations init error

[Pierre-Jean Clément]

Package: update-manager
Followup-For: Bug #650841

message from the UI:
'E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/security.debian.org_dists_lenny_updates_main_binary-i386_Packages, E:Les listes de paquets ou le fichier « status » ne peuvent être analysés ou lus.'

I can't update anymore. What are my options ?

-- System Information:
Debian Release: 5.0.9
Architecture: i386 (i686)

Kernel: Linux 2.6.26-2-686 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages update-manager depends on:
ii  gconf2                   2.22.0-1        GNOME configuration database syste
ii  libgnome2-perl           1.042-1+b1      Perl interface to the GNOME librar
ii  python                   2.5.2-3         An interactive high-level object-o
ii  python-dbus              0.82.4-2        simple interprocess messaging syst
ii  python-glade2            2.12.1-6        GTK+ bindings: Glade support
ii  python-gnome2            2.22.0-1        Python bindings for the GNOME desk
ii  python-support           0.8.4lenny2     automated rebuilding support for P
ii  python-vte               1:0.16.14-4     Python bindings for the VTE widget
ii  software-properties-gtk  0.60.debian-1.1 manage the repositories that you i
ii  synaptic                 0.62.1+nmu1     Graphical package manager
ii  update-manager-core      0.68.debian-7   APT update manager core functional

update-manager recommends no packages.

Versions of packages update-manager suggests:
ii  update-notifier          0.70.7.debian-5 Daemon which notifies about packag

-- no debconf information