แล้วตัวนี้ละครับ Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already

<?php
session_start();
/*
                                 echo $_SESSION["id_user_log"]
                         echo " username = ".$_SESSION["username_log"];
                        echo " <br>password = ".$_SESSION["password_log"];
                        echo "<br>name = ".$_SESSION["name_log"];
                        echo "<br>point = ".$_SESSION["point_log"];
                        echo $_SESSION["id_user_building_log"];
                            echo $_SESSION["id_building_log"];
                            echo $_SESSION["id_place_log"];
                            echo $_SESSION["id_midi_log"];
*/
//assign session varable to normal varable
//for include anypage
								
								$user=$_SESSION["user"];
                              $user_id=$_SESSION["user_id"];
							   $position=$_SESSION["position"];
							  




?>