you are using plesk 8 try the group operations in plesk control panel, all your domains will be set to safe mode.
please confirm about same.. or read the plesk docs.. or manually do the same this way.
add vhost.conf at /var/www/vhosts/domain.com/conf/
with the following lines:
php_admin_value safe_mode Off
/usr/local/psa/admin/bin/websrvmng --reconfigure-vhost --vhost-name=<domain_name>
service httpd restart