[Koha] Corrupted PDF on Batch Export

On Koha 3.03.00.004 using the label creator I have create batches in the past that downloaded as PDFs fine. However the librarian recently added about 100 books to the system manually and in trying to print the labels for a new batch containing those books the PDF file that is downloaded in not valid. I get a message from my reader that the file is damaged. I have created other batches that download fine so it appears there is something in that batch which is causing the problem. Any ideas on where to look? I can download that batch as a CSV. Thanks, Shawn