I am glad that you managed to fix your problem and that my findings were of any help. I might as well go ahead and briefly explain the Program Files (x86) vs. Program Files thing. Since your OS (operating system) is 64-bit, and some programmes have only 32-bit versions, it is required to have both versions of these programmes. The 32-bit versions are stored in Program Files (without x86) and the regular 64-bit versions are in Program Files (x86). Please read
this page for further information on this subject.
Also, if you ever have this problem with other EA-made default neighbourhoods, you should delete the following files and let the game recreate them.
For Twinbrook, - [Game installation location]\Electronic Arts\The Sims 3 Ambitions\Caches\Twinbrook.objectCache
For Bridgeport, - [GIL]\Electronic Arts\The Sims 3 Late Night\Caches\Bridgeport.objectCache
For Appaloosa Plains, - [GIL]\Electronic Arts\The Sims 3 Pets\Caches\AppaloosaPlains.objectCache
For Starlight Shores, - [GIL]\Electronic Arts\The Sims 3 Showtime\Caches\Starlight Shores.objectCache
This problem should not occur with custom worlds (including EA-made Riverview, Barnacle Bay, Hidden Springs and Lunar Lakes), however even if it does, you should delete the two cache files for that world found in the (My) Documents/Electronic Arts/The Sims 3/WorldCaches folder.