The Sims 3 all togeather

I've been having problems saving the game. I get this Error Message (" An unexpected error has occured while saving: error code 12. Please consult the readme for details.") So I consult the read me. I went to  For windows vista cause that's the computer I have my Sims 3 on. And I might not have service pack 1, In which case, If I don't have that installed I'll install it. But I believe I already did install it. For My Processor: Intel(R) Pentium(R) Dual CPU E2200 @ 2.20 GHz and Memory: 3.00GB

I have 318GB free of 456GB

Factory Image is 1.24GB free of 9.23GB.

I have the lates version of directX on my computer.

So lets say I have service pack 1 installed already on my computer, and I have all the rest I told ya. What can I do to fix this error code, because I love playing the Sims 3 and i have not played it because of having problems?

Thanks