[Mimedefang] problem with core dumping

[GVB]

Running:

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FreeBSD domain.com 4.9-STABLE FreeBSD 4.9-STABLE #0: Wed Jan 21 22:32:26 PST 2004     root at domain.com:/usr/src/sys/compile/domain19  i386

Sendmail, mimedefang, spamassasin, clamav.

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Everything had been running perfect, I upgraded mimedefang to 2.39 and now
starting seeing these problems:

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Jan 29 11:52:55 domain mimedefang-multiplexor: Slave 3 stderr: Out of memory!
Jan 29 11:52:58 domain mimedefang-multiplexor: Slave 3 ran out of memory -- poss
ible DoS attack due to complex MIME?
Jan 29 11:52:58 domain mimedefang-multiplexor: Reap: Idle slave 3 (pid 56144) ex
ited due to signal 11 (SLAVE DIED UNEXPECTEDLY)
Jan 29 11:52:58 domain mimedefang-multiplexor: Slave 3 resource usage: req=18, s
cans=18, user=12.971, sys=0.711, nswap=0, majflt=16, minflt=9911, maxrss=31640,
bi=377, bo=699
Jan 29 11:52:58 domain mimedefang[55341]: Error from multiplexor: ERR No respons
e from slave

Jan 28 12:49:44 domain /kernel: pid 48145 (perl), uid 26: exited on signal 11 (core dumped)
Jan 28 16:59:35 domain /kernel: pid 48923 (perl), uid 26: exited on signal 11 (core dumped)
Jan 28 23:39:16 domain /kernel: pid 52273 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 01:02:37 domain /kernel: pid 52725 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 02:25:59 domain /kernel: pid 53154 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 04:22:40 domain /kernel: pid 53716 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 05:46:01 domain /kernel: pid 54093 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 07:09:46 domain /kernel: pid 54330 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 08:33:14 domain /kernel: pid 55005 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 09:56:12 domain /kernel: pid 55342 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 11:19:32 domain /kernel: pid 55756 (perl), uid 26: exited on signal 11 (core dumped)
Jan 29 11:52:58 domain /kernel: pid 56144 (perl), uid 26: exited on signal 11 (core dumped)
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Machine has plenty of free memory, both physical and virtual.

Where do I start troubleshooting this?

Thanks!!

-gvb