Hello Metropolis Woman. (heh heh, I just had to do that
)
Anyway, I agree with Pam, I've had a similar problem when playing a kleptomaniac sim. I had to get the sim invited in so he could steal their stuff and sometimes it seemed almost impossible to catch the darn sims at home!
At night (after midnight) you can't get to them, in the daytime they're at work and in the evening as soon as they're home from work they will leave again to go to the movies or visit other sims or whatever...
There seems to be a really short window for when you can get hold of them sometimes. Maybe she's at the movies with another guy?
Or maybe she got a promotion and she's working more.
I think in Map View if you know any sims in a house you can see who's actually at the house, maybe you can find her that way and see what she's up to?