It is actually a problem with Cobalt's list server for this list and their own DNS. You are probably subscribed to the list using an email address on your machine. We started getting these (identical messages) for one of the people here who recently subscribed to this list using his email address on our server to receive mail.
Thanks very much, that was the answer I was looking for. You are exactly right. I will let cobalt know, though I presume they might know already.
-- James Riordon SysAdmin http://www.amigo-3.com