Marco let me know that he wasn't able to open files generated with FeedJournal on his Linux PDF readers, including Linux-based e-book readers iLiad and Cybook. It turns out that PDF readers running on Windows are more tolerant when parsing the format.
By debugging the problem I found that null characters are appended to the end of the PDF file, making it unnecessarily large and causes problems on Linux. It was an easy fix and everything should now work fine on all operating systems and readers. If you despite this still have problem to open FeedJournal PDF files on a specific piece of software, please let me know. If anyone has an opportunity to try it on the Amazon Kindle reader I would be happy to know the results!
Expect PDF file sizes to shrink by up to a couple of hundred kilobytes with the new code deployed on the web site!