[exim] False negative when filtering incoming email.

Hi,

I got the following email rejected.
rejected HELO from [1.2.3.4]: syntactically invalid argument(s):

HOw can I find out where the problem in the Exim configure file?
I m using Exim4.4, Spamassassin and ClamAV 0.8 in FreeBSD 5.3

Thanks
Sam