Also had to decode the order status and order comments:

Code:
            if ($orders_history->RecordCount() > 0) {   
               while (!$orders_history->EOF) {   
                    if ($orders_history->fields['comments'] != '' && strpos($orders_history->fields['comments'], 'PayPal status:') === false){ 
                        $count_comments++;
                        $pdf->Cell(120, 14, zen_datetime_short($orders_history->fields['date_added']));  
                        $pdf->MultiCell(456, 14, utf8_decode($orders_status_array[$orders_history->fields['orders_status_id']]));                                       
                        $pdf->Cell(27, 14, '', 0, 0, '', 1);
                        $pdf->MultiCell(549, 14, (utf8_decode(zen_db_output($orders_history->fields['comments']))), 'B');  
                        $pdf->SetLineWidth(.5);
                        $pdf->Line(18,$pdf->GetY(),594,$pdf->GetY());                                    
                    } 
                    $orders_history->MoveNext();
                    if (ORDER_COMMENTS_PACKING_SLIP == 1 && $count_comments >= 1) {
                        break;
                    }
                }       
            }