Worked after adding this missing function in the pdf_class.php:
function PutLine()
{
$this->Ln(2);
$this->Line($this->GetX(), $this->GetY(), $this->GetX()+187, $this->GetY());
$this->Ln(3);
}
On the category-to-pdf link:
Fatal error: Call to undefined method PDF::PutLine() in /var/www/w/wp-content/plugins/post2pdf/pdf_class.php on line 299
Individual posts work fine.