optOutUrl refers to /administrator/

When launching mailings, the unsubscribe action

{action.optOutUrl}

refers to the back-end and not to the front-end.
The URL generated is:

http://www.mysite.be/administrator/?option=com_civicrm&task=civicrm/mailing/optout&reset=1&jid=67&qid=71&h=d76222772933cc04

where it should be:

http://www.mysite.be/?option=com_civicrm&task=civicrm/mailing/optout&reset=1&jid=67&qid=71&h=d76222772933cc04

This situation appeared after upgrading to Joomla 1.6 and CiviCRM 4.0.3. This was done by moving from folder /root/joomla/ to /root/ using akeeba back-up.

Both the civicrm.settings.php files and the civicrm.config.php file are up to date and adapted to the new situation.

Currently, the work-around is by using

{action.optOut}