I've been getting this same never ending pause ever since installing Ambitions. I can start a new game and edit the town as much as I want. I can create sims in CAS with no problem. The issue shows up when I go to actually play the game. As soon as I either move in a new family or choose a family to play, the lot loads and that's it. The game clock never moves off of 8am and I can't select anything on the UI or in the game world. It happens every time, doesn't matter which hood I choose the game is simply unplayable.
My system is five years old but still above minimum with a recently upgraded video card, and the game played fine with WA and HELS:
Pentium D 3.00Ghz dual-core
3GB RAM
GeForce GTS 250 with 1024MB RAM Driver version 6.14.12.5721
Over 100GB free HDD space
WinXP SP3
No CC installed All caches cleared
Edit: Uninstalling and reinstalling Ambitions did not work, but messing with my settings in game seems to have done the trick. I set all the graphic options to their minimums, then while exiting and restarting the game a few times brought them all back up to where I had them. The game is now running just fine, no sign of the pause.