@forgotten:
Well, aparantly there IS a problem with the savestates, otherwise they would work, as they did before
Again it's the savestates, not the battery file.
When I load one (it doesn't matter which one or from which game and if it's old or new) there is this little "Loaded state x" at the bottom of the screen, but nothing happens. No crash, no error message, the game just continues like before. If I do this a few times the emulator just quits to Windows, again no crash, no message etc. as if I would have closed it manualy.