Version 3.x of eZ publish will not work with PHP version 5. Check eZ publish requirements before install. Look here http://ez.no/products/ez_publish_cms/info/requirements_for_ez_publish
eZ publish 4.0 will be PHP 5 based. Look here http://ez.no/community/developer/roadmap
Also, FreeBSD 5.3 isn't exactly known for the rock solid stability one would expect from FreeBSD. I'd urge you to upgrade to 5.4 which is definitely better. Or do as we do and stick with 4.11 hoping Dragonfly gets production ready quickly.