IIS 5.0 dies after smtp service fails to send corrupt emai..

Win 2k server IIS 5.0 sporadically shuts down seemingly after a badly
formed email message is sent out. Event Viewer logs first a 4194 COM+
error referencing a custom component with Exception: C0000005.
Immediately afterwards another error 4097 COM+ is logged with this "The
run-time environment has detected an inconsistency in its internal
state. Please contact Microsoft Product Support Services to report this
error. *** Error in __FILE__(926): Application image dump failed.
C:\WINNT\system32\com\dmp\{3832A9AA-8961-421B-8022-E0353556F67E}_2005_03_15_12_00_31.dmp?"
I've installed IISSTATE with -p PID -d -hc to create a log file but of
course now IIS won't die on me. However, while observing the console I
see several of the following:

(7b8.a74): Unknown exception - code 8000d001 (first chance).
(7b8.a74): Unknown exception - code e0000001 (first chance).

This seems to point to possible stack overflow in the mailmsg.dll file
due to a message that's being processed is being corrupted and MS
instructs you to update your service pack, which all of mine are up to
date. Another possibility seems to be the Remote Retry Queue Length
counter may not correctly report the number of messages that are in the
que, it gets full and bombs mailmsg.dll which bombs IIS. And it also
asks that you update your service pack for Aqueue.dll, Mailmsg.dll,
Ntfsdrv.dll, and Smtpsvc.dll which I've done. Does anyone else have
any ideas?

Mark

Whoops, I forgot some info on the Unknown exception:

Modload: 6c950000 6c963000 C:\WINNT\System32\inetsrv\mailmsg.dll
(7b8.a74): Unknown exception - code 8000d001 (first chance)
(7b8.a74): Unknown exception - code e0000001 (first chance)

Mark