Shopping cart / Shipping estimator error

Zen Cart 1.3.8a
Patch: 1::

Linux Server

PHP Version 5.1.6

MySQL 5.0.27

Too many add ons to list.

Hi

I have problem on my shopping cart page. The shipping estimator does not show, and gives error:

Fatal error: Cannot redeclare class order in /var/www/vhosts/xxxxxxxxx/httpdocs/store/includes/classes/order.php on line 1027.

It only happens when Google Checkout is enabled, and when logged in as a customer.

When I click to the next checkout page the shipping estimator shows up as normal.

If I disable Google checkout, everything works OK, even when logged in.
If I log out, everything works OK, even with Google checkout enabled.

Google checkout works fine & shipping rates show up OK when passed across.

Have searched the forums for an answer & tried a few things, i.e made sure no duplicate or old backup files are present etc. , but still have the problem.

Anyone any ideas?

Ok I appear to have solved the problem.

For anyone else who may have the same issue, the line in file /store/includes/modules/shipping_estimator.php

Line #83 : ```
require(DIR_WS_CLASSES . 'order.php');

has been rewritten as 
Line #83 : ```
 require_once(DIR_WS_CLASSES . 'order.php'); 

The shipping estimator now shows up as it should when logged in & google checkout enabled.

Still unsure as to why this should only happen when logged in though.