I have one of these too. I tried to get my sim to walk from her house at 99 Landgraab to the diner. First, she snapped back to the middle of her lot. When I tried making her walk again, I got this error. Then I bought her a bike (sadly, since this girl is for the Questionable Morals Challenge) and tried again with the same error message (it looked about the same at least, it's a pretty long message).