When we try to print an invoice from the Magento admin panel, we get this error message:
Fatal error: Declaration of Zend_Pdf_FileParserDataSource_File::__construct() must be compatible with Zend_Pdf_FileParserDataSource::__construct() in /var/www/html/includes/src/Zend_Pdf_FileParserDataSource_File.php on line 41
We tried to apply the changes suggested in another StackOverflow answer, but we got a blank pdf invoice file.
We are using Magento 1.8 on PHP 5.4.40.
Kindly advise us on how to resolve this issue.