[Exim] Repeat delivery problem

Hi,
I have a nasty email problem, exim is returning "Segmentation+Fault+-+core+dumped at smtp time, instead of returning a 250 OK.
There seems to be no loggin in the syslog, or exim logs to back this up. Any idea what's caused this, and how I can rectify the situation, because exim thinks the message has been received okay, where as the remote server does not.
Is this a bug?

Alex