Warning: require_once(Zend/Pdf/Element.php): Failed to open stream: No such file or directory in /var/www/html/Zend/Pdf/Parser.php on line 21

Fatal error: Uncaught Error: Failed opening required 'Zend/Pdf/Element.php' (include_path='.:/usr/local/lib/php') in /var/www/html/Zend/Pdf/Parser.php:21 Stack trace: #0 {main} thrown in /var/www/html/Zend/Pdf/Parser.php on line 21