no that can't be a bug why ? because it works in here probably you have a typo somewhere also if you have bans already already you must run the included update_bandates.php script
PHP Code:
$get_bans=$DB_site->query("select b.*, u.*, a.username AS warner, w.*, wt.* from ".TABLE_PREFIX."ban_dates as b
LEFT JOIN " . TABLE_PREFIX . "user AS u ON(u.userid = b.banned_user)
LEFT JOIN " . TABLE_PREFIX . "user AS a ON(a.userid = b.banned_by)
LEFT JOIN " . TABLE_PREFIX . "warnings AS w ON(w.wid = b.banned_warning)
LEFT JOIN " . TABLE_PREFIX . "warning_types AS wt ON(wt.tid = w.warned_warning_id)
ORDER BY $orderby LIMIT $startat, $perpage");