Drupal 5.1, with Taxonomy Access, Per-node access and normal access control.
I seem to be unable to deny edit permission to my users for forum posts. That is, except for anonymous and authenticated users without any role, all other roles can edit own and other's posts. I've tried everything, like reproducing the authenticated users permissions in Taxonomy Access and per-node access to all roles except admin, but still: just authenticated have the right permissions but users with roles can edit any forum post.
Is there any other place defining these permissions that I'm overlooking?