KocMocuJIa, всё работает!
$req = mysql_query("SELECT COUNT(*) FROM `users` WHERE `imname` LIKE '" . mysql_real_escape_string($search_db) . "'");
$total = mysql_result($req, 0);
if ($total > 0) {
$req = mysql_query("SELECT * FROM `users` WHERE `imname` LIKE '" . mysql_real_escape_string($search_db) . "' ORDER BY `name` ASC LIMIT $start, $kmess");