php exec() Permission denied for subdomain.sh

[Kevin-fr]

My php file with CHMOD 755 or 777 and GID / UID root return Permission denied, why ??

<?php
$output = shell_exec('/usr/local/psa/bin/subdomain.sh --create mysubdomain -domain mydomain.com 2>&1');
echo $output;
?>

return --> sh: line 1: /usr/local/psa/bin/subdomain.sh: Permission denied

Safe_Mode in my php.ini is turn off :
------------------------
safe_mode = Off
safe_mode_gid = Off
safe_mode_include_dir =
safe_mode_exec_dir =
safe_mode_allowed_env_vars = PHP_
safe_mode_protected_env_vars = LD_LIBRARY_PATH
-------------------------