dvdrip-master (needed for a cluster) does not start : The following Perl modules are needed for the cluster mode: Event

[Mossroy]

Binary package hint: dvdrip

I'm using Ubuntu 10.04 alpha 3, with all current updates.
The cluster feature of dvd::rip does not work.
If you choose "panel control" in the "cluster" menu, you have an error message :
Démarrage impossible du maître local sur le port 28646.
Exécutez dvdrip-master vous-même pour comprendre pourquoi il ne veut pas démarrer.

If I translate it in English, it would be :
Starting local master failed on port 28646.
Launch dvdrip-master to understand why it doesn't start.

If I start dvdrip-master in a terminal, it fails with the following error message :
The following Perl modules are needed for the cluster mode:

    Event

Please read the documentation at:

    http://www.exit1.org/dvdrip/doc/install.cipp#cluster
    http://www.exit1.org/dvdrip/doc/cluster.cipp

dvd::rip is installed in version 1:0.98.11-0ubuntu1 (the one that fixes https://bugs.launchpad.net/ubuntu/+source/dvdrip/+bug/521907 and https://bugs.launchpad.net/ubuntu/+source/dvdrip/+bug/527462 : this is not a duplicate)

I reproduced the same behavior in a freshly installed virtual machine.
Here are the dependencies reported by dvd::rip :

  Programme Version
  -------------------------------
  dvd::rip 0.98.11
  transcode 1.1.5
  ImageMagick 6.5.7
  ffmpeg SVN-r0.5.1-4:0.5.1-1ubuntu1,
  xvid4conf non installé
  subtitle2pgm 0.3
  lsdvd 0.16
  rar 3.90
  mplayer 4.4.3
  ogmtools 1.5
  dvdxchap 1.5
  mjpegtools 1.9.0
  xine 0.99.6
  fping 2.4
  hal 0.5.14
  -------------------------------