Index: wp-admin/nav-menus.php
===================================================================
--- wp-admin/nav-menus.php	(revision 26547)
+++ wp-admin/nav-menus.php	(working copy)
@@ -630,7 +630,9 @@
 						if ( ! empty( $menu_locations ) && in_array( $_nav_menu->term_id, $menu_locations ) ) {
 							$locations_assigned_to_this_menu = array();
 							foreach ( array_keys( $menu_locations, $_nav_menu->term_id ) as $menu_location_key ) {
-								 $locations_assigned_to_this_menu[] = $locations[ $menu_location_key ];
+								if ( isset( $locations[ $menu_location_key ] ) ) {
+									$locations_assigned_to_this_menu[] = $locations[ $menu_location_key ];
+								}
 							}
 
 							/**
@@ -643,10 +645,12 @@
 							$assigned_locations = array_slice( $locations_assigned_to_this_menu, 0, absint( apply_filters( 'wp_nav_locations_listed_per_menu', 3 ) ) );
 
 							// Adds ellipses following the number of locations defined in $assigned_locations
-							printf( ' (%1$s%2$s)',
-								implode( ', ', $assigned_locations ),
-								count( $locations_assigned_to_this_menu ) > count( $assigned_locations ) ? ' …' : ''
-							);
+							if ( ! empty( $assigned_locations ) ) {
+								printf( ' (%1$s%2$s)',
+									implode( ', ', $assigned_locations ),
+									count( $locations_assigned_to_this_menu ) > count( $assigned_locations ) ? ' …' : ''
+								);
+							}
 						}
 						?>
 					</option>