Fatal error: Call to a member function theme() on a non-object

I just got this error when testing the PDF Unformatted style.
Fatal error: Call to a member function theme() on a non-object in /sites/all/modules/views_pdf/views_pdf_template.php on line 857.

Changing it from this

      return $view->field[$template]->theme($row);

To this

      return $view->field[$template]->theme[$row];

at least stops the error message from displaying and shows the fields I wanted displayed in the way I expected.

I'm currently using Views PDF 6.x-1.x-dev (2011-Aug-12).