Phprunner 10 and dompdf plugin

I have installed the dompdf plugin for view the page details in pdf, in my server i have php version 5.6, and i work with Phprunner 10
When I press PDF View button, i receive the error:
Fatal error: Call to a member function getData() on null in ../output/plugins/dompdf/lib/class.pdf.php on line 2369

Thank you for help me.