[Exim] Error in rejectlog

In our rejectlog I see this - many times.

2000-04-01 07:32:01 rejected EHLO from mail.somewhere.com
[208.181.XX.XXX]: syntactically invalid argument(s): (no argument given)

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2000-04-01 07:32:01 rejected HELO from mail.somewhere.com
[208.181.XX.XXX]: syntactically invalid argument(s): (no argument given)



I know that they are running exchange 5.5, but I am unsure of how/where
to look for what is the problem.
Any help and or direction pointing would be app'd...