Validation Show if behaviours not working.

I have a large form that has had 'validation' and 'validation show if' behaviours applied which have been working until recent testing. Not sure at what point it has stopped working.

Page is attached. Any ideas?

Thanks in advance.

OK so I have just been trying removing other behaviours and scripts to test and have just found out by removing the following 'Clear Session' script:

<?php
@session_start();
if ("" == ""){
// WA_ClearSession
$clearAll = TRUE;
$clearThese = explode(",","");
if($clearAll){
foreach ($_SESSION as $key => $value){
unset($_SESSION[$key]);
}
}
else{
foreach($clearThese as $value){
unset($_SESSION[$value]);
}
}
}
?>

They then work. I am sure I have had them working with this present. i have placed this on here to clear any sessions so no-one can be logged in when completing the form. This might happen if more than one person is using the same computer who accesses our site.

Any Ideas?

Only clear the session variables related to login. The validation depends on session variables to work properly.

Specifically list only the session variables associated with login in the clear session variable server behavior and then it won't interfere with the validation.