You still haven't said which version of Zen Cart you are using.
But in the latest version the lines 26-29 quoted in that file reads:
Code:
// strip slashes in case they were added to handle apostrophes:
foreach ($ipn->fields as $key=>$value){
$ipn->fields[$key] = stripslashes($value);
}
You could also try changing this line in includes/languages/english/modules/payment/payapl.php from:
define('MODULE_PAYMENT_PAYPAL_TEXT_CATALOG_TITLE', 'Paypal');
to
define('MODULE_PAYMENT_PAYPAL_TEXT_CATALOG_TITLE', 'Paypal IPN');
and then see if the transactions are listed as Pay Pal IPN and not just Pay Pal.
Vger