Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 17329)
+++ wp-includes/post.php	(working copy)
@@ -1170,6 +1170,8 @@
  * @since 3.0.0
  */
 function _get_custom_object_labels( $object, $nohier_vs_hier_defaults ) {
+	
+	$object->labels = (array) $object->labels; 
 
 	if ( isset( $object->label ) && empty( $object->labels['name'] ) )
 		$object->labels['name'] = $object->label;
Index: wp-includes/taxonomy.php
===================================================================
--- wp-includes/taxonomy.php	(revision 17329)
+++ wp-includes/taxonomy.php	(working copy)
@@ -390,6 +390,8 @@
  */
 
 function get_taxonomy_labels( $tax ) {
+	$tax->labels = (array) $tax->labels; 
+	
 	if ( isset( $tax->helps ) && empty( $tax->labels['separate_items_with_commas'] ) )
 		$tax->labels['separate_items_with_commas'] = $tax->helps;