Is you OS up to date with patches?
FreeBSD.org
(4.62 is the current release right now, you might want to think about installing that)

How about your http server? Is that up to date as well?
Apache.org
(2.0.40 is the latest right now.)

Disable all unneccessary services/daemons on your server!!! This closes the door for vulnerablilites if they exist for that service.
Keep your machines patched!!! This prevents your machine from being an easy target for script kiddies.

My suggestion....rebuild your webserver with the newest FreeBSD, and then install the newest Apache, and make sure all pertinent updates are applied.

Good luck!