Sendmail error causing bogus ticket

I am seeing the following in the rt.log:

[Wed Apr 25 14:22:48 2007] [warning]: /usr/sbin/sendmail exited with
status 17152 (/opt/rt3/lib/RT/Action/

This is followed by:
[Wed Apr 25 14:22:48 2007] [warning]: DBD::mysql::st execute failed:
MySQL server has gone away at
/usr/lib/perl5/site_perl/5.8.5/DBIx/SearchBuilder/ line 505,
line 283.

Any idea how to figure out what is causing this? How to fix this? I have
had reports of this happening to two different users of our RT system.

Thank you