Error PHPEXCEL Call to a member function getNestingLevel() on a non-object
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my code for EXCEL to CSV convert is working... But for a specific Excel file it is coming with error

Call to a member function getNestingLevel() on a non-object in /var/www/portal/user/admin/pe/Classes/PHPExcel/Reader/Excel5.php on line 950

that .xls file have picture and only few rows and columns... Cant get any idea...