I'm having the exact same problem! It's not that the game is crashing, but that it gets stuck on the loading screen that says 'the sims 3 world adventures' and the bar at the bottom of the screen just never fills in.

Have you updated your video drivers recently? If not, try. If you have, try going back to the ones you were using before.

My game isn't responding very well, so I updated my drivers to ones released yesterday. Took forever to get the launcher up and then the screen went to black for a moment and then nada...back to the desktop. Uninstalled the new ones and went back to the old drivers and it all works again. Still choppy though

In order to better solve your problem, please go through the following as listed below:

• Sims 3 - WA/patch 1.6 is crashing/not loading/broken/purple
  World Adventures and patch 1.6 are causing some issues - namely lots turning into blue squares and saving triggering an Error 16. If you have some other issue...
  
  Remove all your custom content from Program Files/Electronic Arts/The Sims 3/Mods/Packages.
  Most mods will not yet be compatible with patch 1.6 or WA. Until the creator uploads an updated version, any hacks cannot be used with patch 1.6 or WA.
  

On occasion you might be asked to do a long FAQ - please make sure you do all the steps and don't just skip over them. You'll often find that these long FAQs have all the details you need. If nothing in the above FAQs fixes your problem you may post again detailing exactly which you have done and which steps failed.