I'm using multiple mail queues with ar_mailer in a project. The sys admin for this project ran into an issue using --chdir
and --table-name via a cron job. It seems the working dir needs to be the rails dir when the constant is loaded (see
exception below). To do this I wrapped self.run in ar_sendmail.rb in the chdir (patch file attached).

Not sure if that's the preferred way to do it, but it seems to work for me. I spent some time trying to write a test
for this, but gave up for now as I was spinning my wheels. If a test is required, feel free to bounce this back to me
and I'll bang on it some more.