Blocking spam coming through chronoforms server side valida

I am trying to block spam that is coming through our forms. I found this code that is supposed to be put into the server side validation I do not know how to tell what version of chronoforms i am using to give that info too. How to i use this code? I cannot find anything that says serverside verification. OR is there a better way, besides a recaptcha image?

<?
if ( in_array($_SERVER['REMOTE_ADDR'], array('94.102.63.15', '58.27.140.58', '72.3.224.55') ) ) {
return "You are not authorized to use this service!";
}
?>

Hi vboss,

The Serverside validation box is at the bottom of the Validation tab in the Form Editor.

Bob