สอบถามปัญหา Warning: Creating default object from empty value ใน nusoap ค่ะ

if(is_array($users)){
    foreach($users as $user){
        //Do something.
    }
}

require_once("lib/nusoap.php");		
		 
		//Define our namespace
		$namespace = "http://localhost/soap_server/webservice.php";
		//Create a new soap server
		$server = new soap_server();
		//Configure our WSDL
		$server->configureWSDL("getCustomer");
		$server->wsdl->schemaTargetNamespace = $namespace;
		
		//Register our method and argument parameters
        $varname = array(
                   'strName' => "xsd:string"
        );
		
		//Add ComplexType
		$server->wsdl->addComplexType( 
			'DataList', 
			'complexType', 
			'struct', 
			'all', 
			'', 
			   array( 
					'id_user' => array('name' => 'id_user', 'type' => 'xsd:string'), 
					'firstname'  => array('name' => 'firstname', 'type'  => 'xsd:string'),
					'username'  => array('name' => 'username', 'type'  => 'xsd:string'),
					'lastname'  => array('name' => 'lastname', 'type'  => 'xsd:string')
		   ) 
		); 
		//Add ComplexType
		$server->wsdl->addComplexType( 
			'DataListResult', 
			'complexType', 
			'array', 
			'', 
			'SOAP-ENC:Array', 
			array(), 
			array( 
				array('ref'=>'SOAP-ENC:arrayType','wsdl:arrayType'=>'tns:DataList[]') 
			), 
			'tns:DataList' 
		); 
				 
		// Register service and method
		$server->register('resultCustomer',$varname, array('return' => 'tns:DataListResult'));
		
		function resultCustomer($strName)
		{
				$objConnect = mysql_connect("localhost","root","") or die(mysql_error());
				$objDB = mysql_select_db("qpt-test");
				$strSQL = "SELECT * FROM qpt_user where firstname like '%".$strName."%'";
				$objQuery = mysql_query($strSQL) or die (mysql_error());
				$intNumField = mysql_num_fields($objQuery);
				$resultArray = array();
				while($obResult = mysql_fetch_array($objQuery))
				{
					$arrCol = array();
					for($i=0;$i<$intNumField;$i++)
					{
						$arrCol[mysql_field_name($objQuery,$i)] = $obResult[$i];
					}
					array_push($resultArray,$arrCol);
				}
				mysql_close($objConnect);
				return $resultArray;
		}
		 
		// 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();