moderator not saved

Hi.
- drupal: 5.0beta1
- activated modules: core + comment + profile + taxonomy + forum + acl + forum_access
- one forum container with three forums

If I try to add a user to the moderator list of the container or one of the forums the user isn't inserted in the acl_users table. After I hit the "Add user" button I am redirected to the forum list (/content/forum) and the message says The forum forum#1 has been updated..
Next time I edit the forum (container) there are no moderators and the acl_users table is still empty.

(btw: thanks for building this module!)