I am not sure what to do for this problem. I asked Hubby about it too. And we're just not sure. You may want to look into Adding Sims 3 and expansions to the DEP, if you haven't already.
The Sims 3 Has Stopped Working (Tips)
http://www.carls-sims-4-guide.com/forum/index.php/topic,20732.msg425117.html#msg425117Other than that, maybe a fresh install might help, if you haven't done it in awhile.
Hmm.. Something else that might be worth trying first is re-tracing the path to the game. Make sure that the path is correct. For example my path is (custom install)
C:\Games\Electronic Arts\The Sims 3\Base Game\Game\Bin\TS3W.exe
By default install paths are:
Digital Download Version
C:\Program Files (x86)\Origin Games\The Sims 3
The Original Disc Version - pre 2012 version
C:\Program Files (x86)\Electronic Arts\The Sims 3
** The newer disc versions may default install to Origin Games.
-- If on 1.67 use the TS3w file. If on 1.69 use the ts3.exe file
I'm not sure if any of this will help, but it maybe worth looking into.