As far as I know, ff the message id:
Message-Id: <mailto:-1704821747.1144160402.oacs@timedeskblog.com&;gt;
is the same for every message being sent you are sending one message from openacs (which is being dealt with wrong by your mail server). if the message id is different you are sending multiple messages from openacs.
By the way, you should edit the page you posted since it contains your users email address and its not good form to post somebodies email address on the internet with a link that can find it (because they will get WAY more spam).
Sadly this message doesn't help (me at least) to know exactly where the problem is. What have you tried from the suggestions above?
