Notice: Use of undefined constant PHPEXCEL_ROOT - assumed 'PHPEXCEL_ROOT' in /home/colegio16/public_html/Classes/PHPExcel/Autoloader.php on line 70

Fatal error: Class 'PHPExcel_Shared_String' not found in /home/colegio16/public_html/Classes/PHPExcel/Autoloader.php on line 11