Would someone who understands log files please help?

I wrote a couple of days ago regarding a problem getting mail
dilevered to my mail server.  I got several good suggestions
from many of you, and I really appreciate it.

I have passed them on to our main mail server administrator.
Unfortunately he is out of town (on training) and the backup staff
is having trouble following up.  We'll see if they can get it worked
out before the regular administrator is back on monday.

IN THE MEAN TIME,  I checked my log files today even though I
am not very knowledgable about their interpretation.  But I
NOTICED SOMETHING THAT WASN'T THERE BEFORE.
There were several entries indicating trouble parsing RF822
headers.  E.g.

"Jun 1999 13:40:25 Error processing file (0010) from
[log in to unmask]:
-> Mail message sent to the LISTSERV address contains invalid
RFC822 fields and could not be parsed successfully."

Could it be that our main mail-server is screwing up the
headers before the messges are delivered to the listserv
machine?   Would someone who understands log files please
help?
Thanks,
--Mike