WP comment notifications bounce back to nobody on server

Hi, I have a client on my server running Word Press 2.0, and every time a comment is posted on one of her entries, it’s trying to deliver a notification (even though this is turned off within the blog).

The bounces look like this:

A message that you sent contained no recipient addresses, and therefore no delivery could be attempted.

—— This is a copy of your message, including all the headers. ——

To:
Subject: TITLE OF BLOG REMOVED New Comment Posted to “”
MIME-Version: 1.0
From: [email protected]
Content-Type: text/plain; charset=”UTF-8″
Message-Id: <[email protected]>
Date: Thu, 10 Aug 2006 16:39:05 -0400

A new comment has been posted to “”: https://domain.com/2006/08/10//
Author:
Message:

——————-

Manage your subscriptions by logging in here: https://domain.com/wp-login.php

Unsubscribe From This Entry https://domain.com/index.php?filosofo_ec_user_id=&check=d3d9446802&filosofo_ec_post_id=&filosofo_ec_subscribe=unsubscribe&email=true

They’re all being delivered to [email protected], of course, since there’s no TO address. The only reason I know this is happening is because I download all nobody messages on the server to find possible issues. However, she’s getting about 50-60 comments a day (most of them are blank, like this one), and it’s getting annoying. Would love to track down the issue and stop this from happening.

I’ve been through the forums and can’t figure out what is causing it. The only thing I can think of is that her blog is either trying to send her notifications when it shouldn’t, but can’t for some reason, or– it’s being exploited by spammers (or they’re ATTEMPTING to use her site to send out bulk messages), like they’ve been doing with aggravating frequency with tons of other php-based web form mail type scripts.

I’m at a loss and could use some help. Thanks in advance.