Index: uc_attribute.module
===================================================================
--- uc_attribute.module	(revision 111)
+++ uc_attribute.module	(working copy)
@@ -482,7 +482,8 @@
   // Convert the attribute and option ids to their current names. This
   // preserves the important data in case the attributes or options are
   // changed later.
-  if (is_array($product->data['attributes']) && is_numeric(key($product->data['attributes']))) {
+  $first_key = array_shift(array_keys($product->data['attributes']));
+  if (is_array($product->data['attributes']) && is_numeric($first_key)) {
     $attributes = array();
     $options = _uc_cart_product_get_options($product);
     foreach ($options as $aid => $option) {