Fatal error: require_once() [function.require]: Failed opening required...

I have Drupal 7.28. Print 7x-2.0 dompdf-0.6.1
When I click on the PDF link on any article, I get the following error:
Fatal error: require_once() [function.require]: Failed opening required '/home/{sitename}/public_html/sites/all/libraries/dompdf-0.6.1/lib/php-font-lib/classes/Font.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/{sitename}/public_html/sites/all/libraries/dompdf-0.6.1/dompdf_config.inc.php on line 332

Would appreciate any feedback about this issue. Thanks!