Add_filter not working after update to 1.6.2

Hello, We had an "add_filter" set up for validation that used to work before upgrading to the latest version. We can not figure out why it isnt working now. Could you please help us figure out why? I have copied and pasted the code below.

[php]
//code

add_filter('gform_validation', 'custom_validation');

function custom_validation($validation_result){

#value = $_POST['input_9'];

$em=$value;

$ar=split("@",$em);

$domain = explode("@", $value);

$domain = $domain[(count($domain)-1)];

$blacklist = array('yahoo-inc.com');

if (in_array($domain, $blacklist)) {

echo $ar[1];

// set the form validation to false

$validation_result["is_valid"] = false;

//finding Field with ID of 1 and marking it as failed validation

foreach($validation_result["form"]["fields"] as &$field){

//NOTE: replace 1 with the field you would like to validate

if($field["id"] == "9"){

$field["failed_validation"] = true;

$field["validation_message"] = "Only commercial (non-free) Email accounts are accepted.";

break;

}
}
}
return $validation_result;
}

// END CODE

Hi Carl,

We didn't change anything with the validation code, the only change was updating to the latest GF (that's when it broke). This is an important customer so we would appreciate getting some help resolving this issue. The PHP validation code has always worked in the past, we need to figure out what changed between this version of GF and the last in order to identify the issue and resolve it.

Thanks.