After changing something in the templates, you should expand the template.
/sbin/e-smith/expand-template /etc/crontab
Then you will probably have to stop / start cron.
service crond restart
Otherwise cron will still be running your old script.
If the > /dev/null doesn't catch all output, just add 2>&1 at the end:
*/10 * * * * /usr/bin/php -f /home/e-smith/files/primary/html/cron.php >/dev/null 2>&1
The >/dev/null takes care of the standard output, the 2>&1 takes care of the errrors.