--- cart.module.183.php	2006-02-26 17:25:29.000000000 -0600
+++ cart.module.php	2006-02-26 17:18:18.000000000 -0600
@@ -619,7 +619,7 @@
     ec_checkout_delete_data();
 
     if ($edit->gross > 0) {
-      $output = module_invoke($edit->payment_method, 'paymentapi', $edit, 'payment page');
+      $output = module_invoke(payment_get_modulename($txn->payment_method), 'paymentapi', $edit, 'payment page');
     }
     else {
       drupal_set_message(t('Your order has been submitted.'));