TL:DR - No matter what game file I open, it says 'Your Empire has been destroyed'. Any idea why?

So I've been playing a while and tested a few different games versions out. After a few false starts, I've now got the hang of what I'm doing so started a new game a few days ago. I've come to load the latest save in that game today and it immediately say 'Your Empire has been destroyed'. No idea why, so I loaded a save in the same game, but a while before the latest save, and it says the exact same thing. So I tried one of the previous game, and it does the exact same thing. I've tried loading every save I have from about five different play through and they all say the same. Anyone any ideas whats going wrong?