using mailman and exim

[Jason Majors <jason@whizzird.net>]

I'm trying to setup a simple mailing list using exim and mailman.

Every minute when the cron runs I get this:
Aug 31 15:21:03 2001 qrunner(16682): Traceback (innermost last):
Aug 31 15:21:03 2001 qrunner(16682):   File "/usr/lib/mailman/cron/qrunner", line 275, in ?
Aug 31 15:21:03 2001 qrunner(16682):      lock.lock(timeout=0.5)
Aug 31 15:21:03 2001 qrunner(16682):   File "/usr/lib/mailman/Mailman/LockFile.py", line 219, in lock
Aug 31 15:21:03 2001 qrunner(16682):      self.__write()
Aug 31 15:21:03 2001 qrunner(16682):   File "/usr/lib/mailman/Mailman/LockFile.py", line 350, in __write
Aug 31 15:21:03 2001 qrunner(16682):      fp = open(self.__tmpfname, 'w')
Aug 31 15:21:03 2001 qrunner(16682): IOError :  [Errno 13] Permission denied: '/var/lib/mailman/locks/qrunner.lock.mystique.16682' 

/usr/lib/mailman and /var/lib/mailman are both owned recursively by
mailman (and in the mailman group). And the cron job was installed as
mailman, so permissions shouldn't be an issue.

I can create a new list, and get the mail as the list administrator,
but subscribe and help requests to test-request@whizzird.net do
nothing. They don't even generate a log entry.
I have the latest exim and mailman from sid.
Can somebody point me in the right direction?

Thanks,
Jason