php Warning: session_start() [function.session-start]: Cannot send session cache limiter มันคืออะไรอะครับแล้วแก้ยังไงได้บ้างครับ

<?php
	session_start();
	if($_SESSION['id_card'] == "" or $_SESSION['id_work'] == "")
	{
		echo "Please Login!";
		exit();
	}

	
	include('connect.php');
	$strSQL = "SELECT * FROM member WHERE id_card = '".$_SESSION['id_card']."' or id_work = '".$_SESSION['id_work']."'";
	$objQuery = mysql_query($strSQL);
	$objResult = mysql_fetch_array($objQuery);
?>