I had the exact same problem.  When I began to look around to see what the problem was, I found out I had several sims 2 mods running in sims 3.  World Adventures will not allow sims 2 mods to run.  Even if you do manage to get it to load with some of the sims 2 mods, it will not run correctly.  So, go back into your mods folder and check each mod to be sure it is a sims 3 mod.