Index: cart/cart.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/ecommerce/cart/cart.module,v
retrieving revision 1.133.2.14.2.10.2.30
diff -u -p -r1.133.2.14.2.10.2.30 cart.module
--- cart/cart.module	13 Jun 2008 01:39:37 -0000	1.133.2.14.2.10.2.30
+++ cart/cart.module	26 Jul 2008 01:50:21 -0000
@@ -126,7 +126,9 @@ function cart_user($op, &$edit, &$user, 
   switch ($op) {
     case 'login':
        // Convert their cart session to a permanent user cart at login.
-      db_query("UPDATE {ec_cart} SET cookie_id = %d WHERE cookie_id = '%s'", $user->uid, session_id());
+      if (isset($_SESSION['cart_id'])) {
+        db_query("UPDATE {ec_cart} SET cookie_id = %d WHERE cookie_id = '%s'", $user->uid, $_SESSION['cart_id']);
+      }
       break;
   }
 }
@@ -940,6 +942,7 @@ function cart_get_id() {
   }
   elseif ($sid = session_id()) {
     // Use session id until the user registers, then switch to user id.
+    $_SESSION['cart_id'] = $sid;
     return $sid;
   }
 }