Converting osc contribution Post code Validation

[vkd1980]

Can any one tell me whats wrong with this function?, I am a Newbie in PHP

Function in "\includes\functions\functions_general.php" to Check

// VALIDATE POSTCODE START
function tep_validate_postcode($country_id, $postcode)
    {
    $postval =$db->Execute( "select countries_postal_validation from countries where countries_id = '" . (int)$country_id . "' limit 1");
    
        if (zen_not_null($postval->fields['countries_postal_validation']))
        {
        return (preg_match($postval->fields['countries_postal_validation'], $postcode));
        }
    else return true;
    }
// VALIDATE POSTCODE END 

Checking of entry in "\includes\modules\pages\address_book_process\header_php.php"

if (strlen($postcode) < ENTRY_POSTCODE_MIN_LENGTH) {
    $error = true;
    $messageStack->add('addressbook', ENTRY_POST_CODE_ERROR);
  }
// VALIDATE POSTCODE START
    if (tep_validate_postcode($country, $postcode) == false)
        {
        $error = true;
        $messageStack->add('addressbook', ENTRY_POST_CODE_VALID_ERROR);
        }
// VALIDATE POSTCODE END 

Thanks in Advance

Vinod