If the following code is commented out, the PDF export works.

//Set some pdf metadata
1676 $lg=array();
1677 $lg['a_meta_charset'] = 'UTF-8';
1678 if (getLanguageRTL($sLanguageCode))
1679 {
1680 $lg['a_meta_dir'] = 'rtl';
1681 }
1682 else
1683 {
1684 $lg['a_meta_dir'] = 'ltr';
1685 }
1686 $lg['a_meta_language'] = $statlangcode;
1687 $lg['w_page']=$statlang->gT("page");
1688 $this->pdf->setLanguageArray($lg);