I am having the same error as mentioned in this post:
http://mail.python.org/pipermail/mailman-developers/2004-June/016931.html

My traceback:
Aug 30 16:52:38 2004 (14988) Traceback (most recent
call last):
  File "/usr/opt/mailman//Mailman/Queue/Runner.py",
line 105, in _oneloop
    self._onefile(msg, msgdata)
  File "/usr/opt/mailman//Mailman/Queue/Runner.py",
line 155, in _onefile
    keepqueued = self._dispose(mlist, msg, msgdata)
  File
"/usr/opt/mailman//Mailman/Queue/IncomingRunner.py",
line 130, in _dispose
    more = self._dopipeline(mlist, msg, msgdata, pipeline)
  File
"/usr/opt/mailman//Mailman/Queue/IncomingRunner.py",
line 153, in _dopipeline
    sys.modules[modname].process(mlist, msg, msgdata)
  File
"/usr/opt/mailman//Mailman/Handlers/ToDigest.py", line
82, in process
    send_digests(mlist, mboxfp)
  File
"/usr/opt/mailman//Mailman/Handlers/ToDigest.py", line
123, in send_digests
    send_i18n_digests(mlist, mboxfp)
  File
"/usr/opt/mailman//Mailman/Handlers/ToDigest.py", line
295, in send_i18n_digests
    msg = scrubber(mlist, msg)
  File
"/usr/opt/mailman//Mailman/Handlers/Scrubber.py", line
257, in process
    url = save_attachment(mlist, part, dir)
  File
"/usr/opt/mailman//Mailman/Handlers/Scrubber.py", line
348, in save_attachment
    fnext = os.path.splitext(msg.get_filename(''))[1]
  File "/usr/opt/mailman//pythonlib/email/Message.py",
line 683, in get_filename
    filename = self.get_param('filename', missing,
'content-disposition')
  File "/usr/opt/mailman//pythonlib/email/Message.py",
line 566, in get_param
    for k, v in self._get_params_preserve(failobj, header):
  File "/usr/opt/mailman//pythonlib/email/Message.py",
line 516, in _get_params_preserve
    params = Utils.decode_params(params)
  File "/usr/opt/mailman//pythonlib/email/Utils.py",
line 337, in decode_params
    charset, language, value =
decode_rfc2231(EMPTYSTRING.join(value))
  File "/usr/opt/mailman//pythonlib/email/Utils.py",
line 283, in decode_rfc2231
    charset, language, s = s.split("'", 2)
ValueError: unpack list of wrong size

s at this point has the value: NET News.com.pdf


What I think are the relavent headers:

X-Mailer: Apple Mail (2.619)
--Apple-Mail-7--372163126
Content-Transfer-Encoding: base64
Content-Type: application/pdf;  x-unix-mode=0644;CNET
News.com.pdf"
Content-Disposition: inline;silicon | C";
        filename*1="NET News.com.pdf"




If you need more information than this, I'll need to
run it past the sender of the message, first.

Logged In: YES 
user_id=31392

Is this a Python bug?  It looks like a Mailman problem?

Logged In: YES 
user_id=7767

Oh. Yes, you're probably right. I saw someone on the mailman
mailing list with the same problem and a response from Barry
Warsaw asking for a ticket to be created, and a link. I
didn't look close to see which project I was leaving a
ticket. I assumed it was a Mailman queue.

Logged In: YES 
user_id=752496

This is (was) a Mailman problem, not a Python bug.

.    Facundo