fetchmail strangeness

[Malcolm Kay]

I'm using fetchmail to retrieve email from my isp, and getting the 
following message in /var/log/maillog repeated at about the fetchmail 
polling rate:

Oct  9 00:00:01 beta sm-mta[5995]: h98EU11h005995: Syntax error in mailbox address "cf4lsn at adsenger.com?" (non-printable character)
Oct  9 00:00:01 beta sm-mta[5995]: h98EU11h005995: from=<FETCHMAIL-DAEMON at beta.home>, size=0, class=0, nrcpts=0, proto=SMTP, daemon=MTA, relay=localhost.home [127.0.0.1]

I haven't been able to find the source of the reference:
cf4lsn at adsenger.com

% cat .fetchmailrc  ->
# Configuration created Mon Feb 17 00:14:20 2003 by fetchmailconf
set postmaster "malcolm"
set bouncemail
set no spambounce
set properties ""
poll mail.internode.on.net with proto POP3
       user 'malcolm.kay' there with password 'xxxxxxxxxxx'

Can anyone please explain what is happening, or bettter still,
how to fix it.

Malcolm