Erro ao exportar planilha em PDF

Ao tentar exportar esta planilha http://www.corais.org/colaborativape/node/79561 em PDF, aparece a seguinte mensagem de erro:

Fatal error: Uncaught exception 'Exception' with message 'PDF Rendering library has not been defined.' in /home/storage/9/7d/cc/designlivre/public_html/sites/all/libraries/PHPExcel/Classes/PHPExcel/Writer/PDF.php:49 Stack trace: #0 /home/storage/9/7d/cc/designlivre/public_html/sites/all/libraries/PHPExcel/Classes/PHPExcel/IOFactory.php(141): PHPExcel_Writer_PDF->__construct(Object(PHPExcel)) #1 /home/storage/9/7d/cc/designlivre/public_html/sites/all/modules/sheetnode/modules/sheetnode_phpexcel/sheetnode_phpexcel.export.inc(72): PHPExcel_IOFactory::createWriter(Object(PHPExcel), 'PDF') #2 /home/storage/9/7d/cc/designlivre/public_html/includes/batch.inc(301): _sheetnode_phpexcel_batch_export_finished(true, Array, Array) #3 /home/storage/9/7d/cc/designlivre/public_html/includes/batch.inc(42): _batch_finished() #4 /home/storage/9/7d/cc/designlivre/public_html/modules/system/system.admin.inc(1829): _batch_page() #5 /home/storage/9/7d/cc/designlivre/public_html/includes/menu.inc(350): system_batch_page() #6 /home/storage/9/7d/c in /home/storage/9/7d/cc/designlivre/public_html/sites/all/libraries/PHPExcel/Classes/PHPExcel/Writer/PDF.php on line 49

Lembrando que nos formatos XLS e XLSX a exportação funciona normalmente.