Blank screen at checkout... 2 occurrences

Hi there,

An addition to this topic... I have blank pages occurring at two places. I have read many posts relating to this issue and have tried a few things (spaces in php files, etc) but no solution yet.

zen-cart version 1.3.8a
store url: store.theebooksale.com
N.B.: Recently moved to a new host/server (1and1)... but everything worked ok before (godaddy).

First instance:
When a paperback is added to the cart and the checkout button is clicked. Note: I use the 'Flat Rate' shipping module for this.
The following error is logged...
[28-Mar-2010 22:38:32] PHP Fatal error: Cannot redeclare class order in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/classes/order.php on line 990

Second instance:
When an ebook is added to the cart and at the final 'Confirm' button in the checkout is clicked. Note: paypal is fine but the blank screen happens when the credit card option (iridium v1.4.2) is used.
The following error is logged...
[28-Mar-2010 23:11:46] PHP Fatal error: Call to a member function getAddressNumericCheckResult() on a non-object in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/modules/payment/iridium.php on line 1973

Final note: I also get this warning for both instances (this refers to an algozone template specific file):
[28-Mar-2010 22:37:37] PHP Warning: reset() [<a href='function.reset'>function.reset</a>]: Passed variable is not an array or object in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/modules/sideboxes/ZC03C00311/currencies_az01.php on line 21
[28-Mar-2010 22:37:37] PHP Warning: Variable passed to each() is not an array or object in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/modules/sideboxes/ZC03C00311/currencies_az01.php on line 22

Anyone any ideas? I can attach some snippets of code if it will help.
Regards,
Richie.

Not sure what I've managed to do... but when I made a small changed to the /includes/modules/payment/iridium.php file, the admin -> module -> payment page now looks like this:

Note: the iridium module should be listed next in the list... and also, the right sidebar is missing.

I uploaded the old iridium.php file again but it makes no difference.
I've not edited any other file.
Anyone any idea what I've done?

Many thanks,
Richie.

... I've fixed the last post issue... my mistake... but the other errors still exist:

myDEBUG-1270005606.log:[30-Mar-2010 23:20:06] PHP Fatal error: Cannot redeclare class order in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/classes/order.php on line 989

myDEBUG-1270005835.log:[30-Mar-2010 23:23:56] PHP Fatal error: Class 'IridiumTransactionType' not found in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/modules/payment/iridium.php on line 1244

An update:

The /includes/classes/order.php file seemed to be an older version (order.php 6534 2007-06-26 01:01:00Z drbyte), so I added the newer version (order.php 7129 2007-09-29 03:03:04Z drbyte) but I still get the error:
myDEBUG-1270008567.log:[31-Mar-2010 00:09:28] PHP Fatal error: Cannot redeclare class order in /var/www/vhosts/store.theebooksale.com/httpdocs/includes/classes/order.php on line 1018

So, which file should I use?
I think the issue is not with this file anyway... so where to next?

Update: an old/backup file was left in the following directory and this caused the blank screen issue:
includes/modules/pages/checkout_shipping/