[CentOS] selinux violation does not get logged

After upgrading to centos 5.4 I am getting a selinux violation, yet
nothing is logged to /var/log/audit/audit.log.  Other violations do get
logged.

The violation occurs when running the following command on the mail
server:

aspen> /usr/bin/Mail centos at centos.org
Subject: test
hi
Cc: 

aspen> send-mail: warning: premature end-of-input on /usr/sbin/postdrop
-r while reading input attribute name
send-mail: fatal: nataraj(500): unable to execute /usr/sbin/postdrop -r:
Success

If I run with "setenforce 0" /usr/bin/Mail works.  With "setenforce 1"
it gets the error above, yet the violation does not get logged, so I
can't tell how to fix it.  Note: /usr/bin/Mail is the postfix version
of /usr/bin/Mail.

Any ideas how I can find out what the violation is so I can add rules to
allow it?

Nataraj