о, не так. вот так
$req_down = mysql_query("SELECT * FROM `down_files` WHERE `type` = '2' ORDER BY `time` DESC LIMIT 1");
if(mysql_num_rows($req_down) > 0) {
$res_down = mysql_fetch_assoc($req_down));
echo '<a href="' . $set['homeurl'] . '/download/index.php?act=view&id=' . $res_down['id'] . '">' . functions::checkout($res_down['rus_name']) . '</a>';
}