Fix preg_match fail

booking.balance.inc

@@ -12,7 +12,7 @@ function booking_balance_page() {
 	$paypal_form = "";
 
 	//verify that arg(1) is a uuid
-	if (! ('/^[0-9A-Fa-f\-]+$/', arg(1))) {
+	if (! preg_match('/^[0-9A-Fa-f\-]+$/', arg(1))) {
 		//parameter from url is not what we were expecting
 		drupal_set_message("Error: Invalid session ID supplied to the balance payment page. Please use the contact us form to let us know.", 'error', FALSE);
 		drupal_goto('<front>');