What I should have said in the first place is that an Error12 is an out of usable resources condition. They can happen on systems that just don't have enough resources to begin with, but also when plenty are available on much stronger systems but the current game session is maxed out as to what it can actually use.
Afraid that 32-bit applications like TS3 are never going to be extended in that regard unless they are entirely reprogrammed or a 64-bit protective overwrap is provided, but only EA can do those things. The overwrap thing has been attempted by experts off to the side, but nothing usable ever came of it, unfortunately. As players we frequently want to push our games to do more than they have been, most of us don't sit down to play with the intent of being as gentle with them as possible for an entire session. Or, at least that's not the first thing I think of when wanting to control and make changes to my sims' environments. ;)