Redmine

Hello,
I've followed the ubuntu's redmine installation guide (here: http://doc.ubuntu-fr.org/redmine , in french), and I passed all the steps with success.
I chosed to access redmine using Apache 2 server, by creating a virtualhost. Here is its content:

<VirtualHost *:80>
  ServerName redmine

  # On paramètre le proxy pour transmettre les requêtes adresées à tracker.lan soient transmises à
  # Redmine (Mongrel est installé en local sur le port 3000)
  ProxyPreserveHost Off
  ProxyPass        /  http://127.0.0.1:3000/
  ProxypassReverse /  http://127.0.0.1:3000/

  # On définit les fichiers de log
  ErrorLog /opt/redmine/log/apache-error.log
  CustomLog /opt/redmine/log/apache-access.log combined
</VirtualHost>

I've activated it well, and it's accessible in the domain redmine.

I first got a 403 error (Forbidden Access), and I changed the configuration of the apache proxy (/etc/apache2/mods-available/proxy.conf file) to allow access to the Mongrel's Redmine server.

But now, when I try to access to the redmine domain, I get a 503 error (Service Temporarily Unavailable).

Here is the content of the /opt/redmine/log/apache-error.log file:

[Wed Jan 05 11:11:24 2011] [error] [client 127.0.0.1] client denied by server configuration: proxy:http://127.0.0.1:3000/
[Wed Jan 05 11:11:24 2011] [error] [client 127.0.0.1] client denied by server configuration: proxy:http://127.0.0.1:3000/favicon.ico
[Wed Jan 05 11:11:27 2011] [error] [client 127.0.0.1] client denied by server configuration: proxy:http://127.0.0.1:3000/favicon.ico
[Wed Jan 05 11:13:25 2011] [error] [client 127.0.0.1] client denied by server configuration: proxy:http://127.0.0.1:3000/
[Wed Jan 05 11:13:35 2011] [error] (111)Connection refused: proxy: HTTP: attempt to connect to 127.0.0.1:3000 (127.0.0.1) failed
[Wed Jan 05 11:13:35 2011] [error] ap_proxy_connect_backend disabling worker for (127.0.0.1)

I didn't find any solution by searching on the net, can someone help me to solve this issue ?
Thanks.