diff -r 889301acc299 -r 7d1ff2f621c7 src/group_cmd.cpp
--- a/src/group_cmd.cpp	Sun Feb 03 20:34:26 2008 +0000
+++ b/src/group_cmd.cpp	Mon Mar 10 15:26:39 2008 +0000
@@ -134,6 +134,9 @@
 			if (v->group_id == g->index && v->type == g->vehicle_type) v->group_id = DEFAULT_GROUP;
 		}
 
+		/* Update backupped orders if needed */
+		if (_backup_orders_data.group == g->index) _backup_orders_data.group = DEFAULT_GROUP;
+
 		/* If we set an autoreplace for the group we delete, remove it. */
 		if (_current_player < MAX_PLAYERS) {
 			Player *p;