Call to a member function cellExists() on a non-object /phpexcel/Classes/PHPExcel/Calculation.php on line 3241

PHP Fatal error:  Call to a member function cellExists() on a non-object in /home/edata/eframework/web/framework/vendors/phpexcel/Classes/PHPExcel/Calculation.php on line 3241

$objPHPExcel->getActiveSheet()->setTitle('图表分析');
$objWorksheet = $objPHPExcel->getActiveSheet();
$objWorksheet->fromArray($newarraydata, NULL, 'AA1');
 $dataseriesLabels = array(
       new PHPExcel_Chart_DataSeriesValues('String', 'Worksheet!$AB$1', NULL, 1),
);

//正确的应该是：

 $dataseriesLabels = array(
       new PHPExcel_Chart_DataSeriesValues('String', '图表分析!$AB$1', NULL, 1),
);