Nasty Bug

I'm at the end of my game; I only need to invade the Torian home world. So I send in some battleships and a transport. The problem is that I cannot attack this last world with either the battleships or the transport. When I click the world to get some info about it an Arcean battleship moves to the front of the screen over the planet, but I cannot attack the Arcean either. Also the Arceans are extinct. I still have the saved game, if you want me to upload it to you just tell me where.