php problem to execute CutyCapt command

i'm having this problem

sh: CutyCapt: Permission denied

my php code is

<?php 
       echo exec('CutyCapt --url=http://www.google.com --out=/var/www/google.png --javascript=on 2>开发者_开发知识库&1');
?>

When calling an executable from PHP, it is called with the permissions of the user PHP runs as (often the Apache server, for example).

That user account does not have permission to call that executable - probably because it belongs to a different user, and has the "executable" bit only for that user or group.

That's all that can be said for sure without more information.