Marc,

Sorry to hear of your troubles.

Firstly - doesn't help you right now but a lesson to us all - test everything first on your new server BEFORE moving live sites across. If things don't work as before stay put until all issues are resolved.

Having said that some moves are not planned - your original server may have fried and this was a forced move rather than a planned one.

The short term solution is to switch back to your old server, if this is possible, until you get this issue resolved.

There is a lack of info as to exactly what is happening but I am assuming that everything goes well with WorldPay and the transaction is completed but the callback fails so you have the transaction details in your WorldPay Control Panel but no order in your Zencart. You may also have had notification from WorldPay that the callback failed - in which case what error was reported? The usual one is that there was some kind of re-direct. WorldPay (presumably for security reasons) does not allow the callback to be re-directed.

It has puzzled me for some time now why the WorldPay module works perfectly on most servers but not all. I think I have narrowed the cause down a bit. This could be a sessions issue. You need to ask your host if they maintain sessions - some do not guarantee to do so. If the session is not maintaned by your server throughout the WorldPAy transaction process then when WorldPay initiates the callback Zencart tries to re-create the session by re-directing to the log in page. As soon as WorldPay detects the re-direct the callback fails.

Things to check:

In your configure.php file at line 55 what do you have?

If this:

Code:
define('STORE_SESSIONS', ''); // use 'db' for best support, or '' for file-based storage
then ensure that your session directory, as defined in Admin >> Configuration >> Sessions, is writeable.

Alternatively try changing the above line 55 to:

Code:
define('STORE_SESSIONS', 'db'); // use 'db' for best support, or '' for file-based storage
If this doesn't work and your host can't help PM me with your email address and I will contact you directly.

If you find a solution post details back here.

Regards,

Alan