[Exim] Exim rejecting email routed from ISP

I get email from two sources, my own domain which uses a dynamic dns
assignment (through dyndns.org) and from my ISP (dccnet.com). Until
yesterday, when I attempted to upgrade to exim 4.05 (I am currently
using 3.35 as part of Debian woody), everything worked fine (except,
as Nigel can tell you, when spamassassin got out of hand). I had to
re-install 3.35, and tidied up the spamassassin contents of exim.conf,
and ever since, though mail to my domain comes through fine,
everything coming from dccnet.com (via fetchmail) gets bounced. I
have searched through the archives, but nothing seems to deal with
this, nor can I find anything in the FAQ. I'm sure it's a simple
matter, but at the moment I'm too thick to see it.

Here is an example:

Your message has encountered delivery problems to the following
recipient(s):

root@localhost
Delivery failed

Unable to deliver to destination domain
Mail server at localhost [127.0.0.1] has the same MailSite serial
number (32073) as this machine.

Reporting-MTA: dns; yoda.dccnet.com
Received-From-MTA: dns; treehouse.ellisonet.ca (unverified [24.207.9.73])
Arrival-Date: Fri, 19 Jul 2002 00:04:39 -0700

Final-Recipient: rfc822; root@localhost
Action: failed
Status: 5.3.0 (Permanent failure - system: no additional status information
available)

I have data from eximon and exim.conf organized, but I don't want to
waste bandwidth. If anyone needs to see those, I'll send them along
as well.

Thanks for any help anyone can provide

Cheers

Cam

--
Cam Ellison Ph.D. R.Psych.
From Roberts Creek on B.C.'s incomparable Sunshine Coast
cam@???
camellison@???
cam@???