If you could find out which version you have and where you purchased the game that would also help. It would also help to know what you are running the game on (Windows, Mac, iPod, etc)
I'll link the answer from LDW's Support FAQ so you can view it for your particular operating system:
WindowsiPhone/iPod TouchBest of luck!
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Edit: Actually, what is not saving? If you can tell that time is passing properly and your peeps are passing away what part of your game is not saving?
As long as there is food in the fridge and they are given their proper medication when they are ill, they shouldn't pass away.. is this the part that is not saving?
You can also pause the game if you feel that you can't tend to them too often.