Upgrade from Ubuntu 5.10 to 6.06 errors on coreutils_5.93-5ubuntu4_i386.deb

[PetrB]

I atempted to upgrade Ubuntu from 5.10 to 6.06. During installation of upgrades the tool reports "Could not install '/var/cache/apt/archives/coreutils_5.93-5ubuntu4_i386.deb'".
and "subprocess pre-installation script returned error exit status 2".

(I have read the DapperReleaseNotes.)

How did I get there:
1) Run System>Administration>Update Manager
The Update Manager offered upgrade to 6.06.
2) Click Upgrade button
The tool will warn that downloading won't be cancellable and start downloading.
After downloading the procedure contines to probably install the new things. When it reached approx 10%, the mesasge above showed.
3) I clicked OK
The tool
The upgrading tool expands embended terminal window and apparently continues doing something (sorry, I did not watch it.)

Then it displayed:

Could not install the upgrades
The upgrade aborts now. Your system can be in an unusable state. A recovery was run (dpkg --configure -a).
installArchives() failed

[PetrB (petr-bug)]

I have played a little with Synaptic and managed to obtain detailed info:

debconf: unable to initialize frontend: Gnome
debconf: (Can't locate object method "signal_connect" via package "Gtk2::Window" at /usr/share/perl5/Debconf/FrontEnd/Gnome.pm line 73, <> line 1.)
debconf: falling back to frontend: Dialog
(Reading database ... 82222 files and directories currently installed.)
Preparing to replace coreutils 5.2.1-2ubuntu2 (using .../coreutils_5.93-5ubuntu4_i386.deb) ...
Removing `local diversion of /usr/share/man/man1/md5sum.textutils.1.gz to /usr/share/man/man1/md5sum.1.gz'
dpkg-divert: rename involves overwriting `/usr/share/man/man1/md5sum.textutils.1.gz' with
  different file `/usr/share/man/man1/md5sum.1.gz', not allowed
dpkg: error processing /var/cache/apt/archives/coreutils_5.93-5ubuntu4_i386.deb (--unpack):
 subprocess pre-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/coreutils_5.93-5ubuntu4_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:

Workaround:
I do not know which file was about to overwrite which file - in fact I do not care. I moved both files out o a way, repeated the upgrade form Synaptic and all goes fine.