--- a/date_elements.inc
+++ b/date_elements.inc
@@ -101,13 +101,13 @@
     '#type' => 'date_combo',
     '#theme_wrappers' => array('date_combo'),
     '#weight' => $delta,
-    '#default_value' => isset($items[$delta]) ? $items[$delta] : '',
+    '#default_value' => isset($items[$delta]) ? $items[$delta] : array(),
     '#date_timezone' => $timezone,
     '#element_validate' => array('date_combo_validate'),
     '#date_is_default' => $is_default,

     // Store the original values, for use with disabled and hidden fields.
-    '#date_items' => isset($items[$delta]) ? $items[$delta] : '',
+    '#date_items' => isset($items[$delta]) ? $items[$delta] : array(),
   );

   $element['#title'] = $instance['label'];