Re-ran the update using the console... I think it was getting hung on this error:
"
2011-10-15 20:27:21 -0400 migration.pl cleaning up lockfile /var/tmp/migration
</dbmigration time="2011-10-15 20:27:21 -0400" >
Stopping Symantec Messaging Gateway Control Center:
[ OK ]
MySQL: skipping stop
Giving mysqld a couple of seconds to exit nicely
E: Sub-process /bin/rpm returned an error code (255)
Err Inappropriate ioctl for device
mount: /opt is busy
[Sat Oct 15 20:41:54 EDT 2011] System is running rc 6. Starting timer.
"
Found this article: http://www.symantec.com/business/support/index?page=content&id=TECH169628
and the reinstall appears to have solved the problem. (sigh of relief)