When trying to output a "book" as PDF, I got "An error occured on the render server: error executing command 'render': [Errno 13] Permission denied: '/opt/mwlib/var/cache/pdfserver/d/de' "
(To my layman's eye this looks like a general error, that was not specifically caused by any of the articles I wanted to include in the book, which was by the way assembled for test purposes. But if I can help with further details, I'll be glad.)
Regards, Michael