Error 403 about php file after installation

[huming17]

i am install the ispcp follow the http://www.isp-control.net/documentation...on:freebsd correctly

and the system is freebsd 8,

but when i login the admincp ,

there is a info about Error 403,for index.php,

i added some html file in admincp gui folder ,it works;
when i add a test.php like just(<?php echo "ok"; ?>);
it could not run with php
ps:i am select fcgid when in installation,and opened it;

someone could help me to solve this problem?
Thanks!