This did the job. Now i am facing more install problems.
- i created a category and a forum but no forums show up on forum list in the admin perspective.
- if i try to insert a user in the admin interface i only get the list of forums (list.page)
- if i try to change my configuration i get a exception (java.io.IOException: The request '/forum/adminConfig/edit/dateTimeFormat.page' is not valid. A correspondent URL Pattern was not found)