fatel error - site gone blank

I was hacked by the iframe virus almost 4 days ago and am still trying to get things back in place i got my site fully operational this morning when a customer reported that when you leave the final stage of the checkout the site goes blank.

I got this error and looked and reloaded some file with the header cannot be set error now its all blank and this is the main error in the log file.

PHP Fatal error: Cannot redeclare class paypalwpp in /hermes/bosweb/web164/b1643/sl.thechess/public_html/shop/includes/modules/payment/paypalwpp.php on line 2981

PHP Fatal error: Cannot redeclare zen_exit() (previously declared in /hermes/bosweb/web164/b1643/sl.thechess/public_html/shop/includes/functions/functions_general.php:19) in /hermes/bosweb/web164/b1643/sl.thechess/public_html/shop/includes/functions/functions_general.php on line 1542

iv searched the web and the forum and i get othing with the zen_exit() function

please help i am desperate here

My life is coming apart because of this

To make matters worse

The payment module in the admin page is looking like this

http://www.thechessfactory.com/images/Fullscreencapture21112009074518.bmp.jpg

the paypal website pro module has been disabled.

I though if I can reinstall this it should do the job.

But im just guessing in thin air

i had set paypal module to send me a error report via email

this is what i got

Now in markflow mode.
SESSION[sendto] = 1

(live transaction) --> https://api-3t.paypal.com/nvp
Request Headers:
Array
(
   [0] => Content-Type: text/namevalue
   [1] => X-VPS-Timeout: 45
   [2] => X-VPS-VIT-Client-Type: PHP/cURL
   [3] => X-VPS-VIT-Integration-Product: PHP::Zen Cart - WPP-NVP
   [4] => X-VPS-VIT-Integration-Version: 1.3.8a
)


Request Parameters: {SetExpressCheckout}
Array
(
// some parameter i had to remove 
just standard stuff like address name and email
}
Response:
Array
(
   [TOKEN] => EC-7CA82346E8078890D
   [TIMESTAMP] => 2009-11-21T11:40:19Z
   [CORRELATIONID] => 1842f1a211075
   [ACK] => Success
   [VERSION] => 3.2
   [BUILD] => 1105502
   [CURL_ERRORS] =>
)

From what i found on the forum Drbyte said in another link

"cannot redeclare class" means that somewhere in your program code that class is being loaded twice.
You'll have to hunt down where it's loaded and stop it from loading a second time.
Perhaps you have duplicate or backup copies of files that are getting automatically loaded ?

https://www.zen-cart.com/tutorials/index.php?article=38
https://www.zen-cart.com/tutorials/index.php?article=39

I just reinstalled zen cart and it all works fine

i guess ill never know till next time