I also installed the Private Messaging mod. I suppose the logout link might have been overwritten then. Unfortunately the computer where I have stored the PunBB distribution archive is currently offline, so I can't verify.
2 2008-04-28 13:38
Re: Logout Problem (12 replies, posted in PunBB 1.2 troubleshooting)
Actually PunBB 1.2.17 was released with a broken Logout link. I dled from the official site and got this problem.
Correct link in include/functions.php should look like:
<a href="login.php?action=out&id='.$pun_user['id'].'&csrf_token='.sha1($pun_user['id'].sha1(get_remote_address())).'">'.$lang_common['Logout'].'</a>