[Exim] Exim Crashes out with Signal 10

Greetings,

    While doing a particularly heavy batch of mailings (>150,000), Exim
was able to send out about 30,000 messages/hr. without problems.  However,
toward the end of the batch when it was running at a much slower rate
because the bulk of it had already been moved, I get a lot of errors that
look like:

/kernel: pid XXXX (exim), uid X: exited on signal 10

    Probably about 40-50 of them so far.  Any clues as to why this might
be happening?  It appears to be happening even when the load is very low (<
.5).  I'm running FreeBSD 3.2-Stable.

    Thanks,
    YL