Missing suphp config on your system.
Follow this:
1. select suphp_worker/_event in 'website config' and better select 'php' (because already as 5.3 and php53u have a problem with centos 6)
2. try reinstall suphp with 'yum reinstall mod_php'
3. Modified code inside /home/apache/etc/suphp.conf from:
...
x-httpd-php="php:/usr/bin/php-cgi"
x-httpd-php52="php:/usr/local/lxlabs/ext/php/bin/php_cgi"
...
to:
...
x-httpd-php="php:/usr/bin/php-cgi"
; x-httpd-php52="php:/usr/local/lxlabs/ext/php/bin/php_cgi"
x-httpd-php52="php:/usr/local/lxlabs/ext/php/etc/lxphpcgi.sh"
...
4. copy /home/apache/etc/suphp.conf to /etc/suphp.conf and to /usr/local/lxlabs/kloxo/file/apache/etc/suphp
5. Rename /etc/httpd/conf.d/suphp.conf to /etc/httpd/conf.d/suphp.nonconf
6. Copy /home/apache/etc/conf.d/suphp52.conf to /etc/httpd/conf.d/suphp52.conf
7. Add in most top in .htaccess on domain root dir with 'AddHandler x-httpd-php .php' (using suphp for primary-php) or 'AddHandler x-httpd-php52 .php' (using suphp for secondary-php)