EMINEM,
$req = mysql_query("
SELECT `forum`.*, `users`.`sex`, `users`.`rights`, `users`.`lastdate`, `users`.`status`, `users`.`datereg`
FROM `forum` LEFT JOIN `users` ON `forum`.`user_id` = `users`.`id`
WHERE `forum`.`type` = 'm' AND `forum`.`refid` = '$id'"
. ($rights >= 7 ? "" : " AND `forum`.`close` != '1'") . "$sql
ORDER BY `forum`.`id` $order LIMIT $start, $kmess
");Добавь там `users`.`alias`