Error code 12 is due to memory, When you get that error (or any error) you will get bad saves and you need to remove those saves. In my documentnts to Electronic Arts Folder to the sims 3 folder. In the sims folder you will find the saves folder. In the saves folder delete any saves that have "Bad" on the end of them.
Also dont use your save option use the "Save As:" feature below save. Rename your file and save as. This gives you a clean save and does not overwright the previous save. Using regular save overwrights your game and could be come corrupt.
also delete your Cashe files very time you play it cleans the game without deleting anything from the game. You should remove these files before you start your game, the game will generate new ones. http://simswiki.info/wiki.php?title=Game_Help:Sims_3_Delete_Cache_Files
If the game was jamming every 10 minutes before all the error 12, make sure your computer meets the requirements to play the game. This game has some pretty high requirements. http://simswiki.info/wiki.php?title=Game_Help:TS3_System_Requirements
