Can't send messages to mailing list or subscribe (no space left on device)

Just got the following message when trying to post to the list:

<rails@lists.rubyonrails.org>: Command died with status 1:
  "/usr/local/mailman/postfix-to-mailman.py". Command output: Traceback
(most
  recent call last): Logging error: <StampedLogger to
  '/usr/local/mailman/logs/error'> Traceback (most recent call last):
File
  "/usr/local/mailman/Mailman/Logging/Logger.py", line 91, in write
  f.write(msg) File "/usr/local/lib/python2.4/codecs.py", line 501,
in
  write return self.writer.write(data) File
  "/usr/local/lib/python2.4/codecs.py", line 179, in write
  self.stream.write(data) IOError: [Errno 28] No space left on device
  Original log message: [Errno 28] No space left on device

Also, when I try to subscribe another email address to the list, I get
the following:

Bug in Mailman version 2.1.5

We're sorry, we hit a bug!

If you would like to help us identify the problem, please email a copy
of this page to the webmaster for this site with a description of what
happened. Thanks!
Traceback:

Traceback (most recent call last):
File "/usr/local/mailman/scripts/driver", line 87, in run_main
   main()
File "/usr/local/mailman/Mailman/Cgi/subscribe.py", line 91, in main
   mlist.Lock()
File "/usr/local/mailman/Mailman/MailList.py", line 159, in Lock
   self.__lock.lock(timeout)
File "/usr/local/mailman/Mailman/LockFile.py", line 243, in lock
   self.__write()
File "/usr/local/mailman/Mailman/LockFile.py", line 424, in __write
   fp.close()
IOError: [Errno 28] No space left on device

I realize that this message probably won't make it to the list, given
the above problems, but I figured I'd try just for the hell of it..

Mike