No, the render server was not ok, sorry :-(
I've restarted the software, it should be working again.
We're running some older version of the software on the server which
has a known bug with hanging processes which fill up the queue from
time to time. As soon as possible (which sadly isn't right now for
technical reasons) we'll update the software on the server to put an
end to this recurring situation.
-- Johannes
WikiEducator is working for me. (And we use our own renderer, so it
wouldn't be related to the PediaPress server when it does fail.)