สอบถามปัญหา error การ call webservice ค่ะ อยากทราบว่าเกิดจากอะไร

<?
		require_once("lib/nusoap.php");
		 
		//Create a new soap server
		$server = new soap_server();
		 
		//Define our namespace
		$namespace = "http://localhost/nusoap/WebServiceServer.php";
		$server->wsdl->schemaTargetNamespace = $namespace;
		 
		//Configure our WSDL
		$server->configureWSDL("SPUGuide");
		 
		// Register our method and argument parameters
        $varname = array(
                   'idAction' => "xsd:string",
				   'obj' => "xsd:string"
        );
		
		$server->register('ServiceData',$varname, array('return' => 'xsd:string'));
		function ServiceData($idAction,$obj)
		{
			
			$hostname = "localhost"; //ชื่อโฮสต์
			$user = "root"; //ชื่อผู้ใช้
			$password = ""; //รหัสผ่าน
			$dbname = "test"; //ชื่อฐานข้อมูล
			// เริ่มติดต่อฐานข้อมูล
			$dbCon=mysql_connect($hostname, $user, $password) or die("ติดต่อฐานข้อมูลไม่ได้");
			// เลือกฐานข้อมูล
			mysql_select_db($dbname,$dbCon) or die("เลือกฐานข้อมูลไม่ได้");
			mysql_query('SET CHARACTER SET UTF8');
			switch($idAction){
				case 'Subject':
					$strSQL = "SELECT * FROM subject order by ID_Sub";
					$result = mysql_query($strSQL);
					$intNumField = mysql_num_fields($result);
					$resultArray = array();
					while($obResult = mysql_fetch_array($result)){
						$arrCol = array();
						for($i=0;$i<$intNumField;$i++){
							$arrCol[mysql_field_name($result,$i)] = $obResult[$i];
						}
						array_push($resultArray,$arrCol);
					}
					mysql_close($dbCon);
					header('Content-type: application/json');
					return json_encode($resultArray);
					break;
				case 'Schedule':
					$strSQL = "SELECT * FROM schedule Where ID_Sub = '".$obj."' order by ID_Sec";
					$result = mysql_query($strSQL);
					$intNumField = mysql_num_fields($result);
					$resultArray = array();
					while($obResult = mysql_fetch_array($result)){
						$arrCol = array();
						for($i=0;$i<$intNumField;$i++){
							$arrCol[mysql_field_name($result,$i)] = $obResult[$i];
						}
						array_push($resultArray,$arrCol);
					}
					mysql_close($dbCon);
					header('Content-type: application/json');
					return json_encode($resultArray);
					break;
			}
		}
		
		// Get our posted data if the service is being consumed
		// otherwise leave this data blank.
		$POST_DATA = isset($GLOBALS['HTTP_RAW_POST_DATA']) ? $GLOBALS['HTTP_RAW_POST_DATA'] : '';
		 
		// pass our posted data (or nothing) to the soap service
		$server->service($POST_DATA);
		exit(); 
?>