Error message with PayPal, and now fatal error

[Frameskin]

Hello

 

I recently upgraded my shop (due to OnePageCheckout breaking something when I when to uninstall it) but since the upgrade I have been receiving error messages about the shopping cart totals not adding correctly.

Here's the error message

 

A client has encountered a problem with the module PayPalAPI, see the report:

 

PayPal response:

TIMESTAMP -> 2012-04-30T19:01:03Z

L_ERRORCODE0 -> 10413

L_SHORTMESSAGE0 -> Transaction refused because of an invalid argument. See additional error messages for details.

L_LONGMESSAGE0 -> The totals of the cart item amounts do not match order amounts.

L_SEVERITYCODE0 -> Error

PayPal returned error

 

Having a look at the cart items I can see that one of the items (one that contains a combination) shows an incorrect value. One of my customers today said that the price of the item only changed once he logged in as a registered customer. I am using PS 1.4.6.2 and my paypal gateway version is 2.8.5

 

Thinking the paypal version might be out of date/problematic, I downloaded the latest version from Prestashop Add-ons and after applying it I now get a fatal error message

 

Fatal error: Cannot make static method ModuleCore::display() non static in class PayPal in /home/frames27/public_html/modules/paypal/paypal.php on line 1362

 

Can someone help me please.

Alan

Any advice on what I can do to effect a fix?