Index: wp-includes/taxonomy.php
===================================================================
--- wp-includes/taxonomy.php	(revision 7935)
+++ wp-includes/taxonomy.php	(working copy)
@@ -1057,7 +1057,7 @@
 	if ( count($taxonomies) > 1 ) {
 		foreach ( $taxonomies as $index => $taxonomy ) {
 			$t = get_taxonomy($taxonomy);
-			if ( is_array($t->args) && $args != array_merge($args, $t->args) ) {
+			if ( isset($t->args) && is_array($t->args) && $args != array_merge($args, $t->args) ) {
 				unset($taxonomies[$index]);
 				$terms = array_merge($terms, wp_get_object_terms($object_ids, $taxonomy, array_merge($args, $t->args)));
 			}