atd woes

[Robin Green]

I previously used the "at" command successfully to schedule downloads
to run at night, when my internet connection is unmetered. Recently,
when I tried to use it, I encountered two problems:

1. Running "at midnight" as my normal logged-in user (rather than as
root), fails with this message:

PAM failure: Failure setting user credentials
You do not have permission to use at.

2. I can schedule the job as root OK, but it doesn't appear to have
succeeded. I haven't received any mail from atd about this (but
/var/spool/mail/root hasn't received any mail since July, and I don't
know where root's mail is now being delivered to, if anywhere!) The
only information I can find about what happened is this single line in
/var/log/messages:

Sep 25 00:00:00 fedora atd[3867]: Failure setting user credentials

So basically it's the same error message occuring both times - but at
different stages in the process. For a normal user you get the
credentials error immediately - for root you get it when the task is
scheduled to run.

So, any ideas?
-- 
Robin