5
you should set permissions correctly for all groups and this is rather hard to manage.
but it seems there is a minor issue in newbb permissions too.
if a user is a forum moderator but dont have access to "post" it still should have all access like webmaster.
to fix this in 3.08
open class/forum.php line 569
change this:
if (newbb_isAdministrator()) return true;
with this:
if (newbb_isAdmin($forum)) return true;
newbb_isAdmin is a more general function and return true if a user is forum moderator so it is better to check just a module admin.