two strange problems with ntpd (OpenBSD 5.1)

[Bahador NazariFard]

#echo servers pool.ntp.org  > /etc/ntpd.conf
# ntpd
this command never change local system time

#ntpd -s
change local system time but I have very strange problem in php
#echo  echo '<?php `ntpd -s` ?>'|php-5.3
above command never  exit.