Hello have installed Fast and East Checkout 1.08 to Zen Cart 1.3.7.

I receive this error when I press "checkout" to proceed to PayPal IPN, my only payment method.

Fatal error: Cannot redeclare class base:order in /clientdata/clients/c/o/coolglobal.com.au/www/includes/classes/order.php on line 20

This is line 20, 21 & 22 of order.php

20 class order extends base {

21 var $info, $totals, $products, $customer, $delivery, $content_type, $email_low_stock, $products_ordered_attributes,

22 $products_ordered, $products_ordered_email;

Please help!