Out of the blue this error message appeared and ruined my day. I have no idea what caused it and I racked my mind senseless thinking of possible explanations. I spent an age trying to fix it. First I tried loading the backup files, but even they would not save. After that I loaded up another...
Thanks very much chaps. I can't believe it's taken me so long to figure that out. I feel so silly. I've had the game sitting there since yesterday too oO)