404 on link to edit contact with contact hash
I tend to use this for my instructions on adding tokens - which in the case of joomla says the url construction should be like 

Joomla!: http://www.myorganization.org/index.php?option=com_civicrm&amp;task=civicrm/profile/edit&amp;reset=1&amp;gid=N&amp;{contact.checksum}&amp;id={contact.contact_id}