You can enable this module by creating a symbolic
link from /var/www/conf/php5.sample/chroot.ini to
/var/www/conf/php5/chroot.ini.

ln -fs /var/www/conf/php5.sample/chroot.ini \
        /var/www/conf/php5/chroot.ini

If you already have Apache running on your machine,
you should not use "apachectl restart" - instead,
you should fully stop and then restart the server.
