It is supposed to get sims off the driveway where the car parks. It's just over zealous and thinks the sim driving the car is in the way of the car after getting out.
As a rule of thumb, any hack that overrides a social interaction will interfere with nightlife. They have completely overhauled the social globals, to the extent that a call to a semi-global may not be the same routine as in previous versions.
Just because you never had a nanny does not mean the portal has not been deleted. The nanny is just a manifestation of the error, not the error itself. (Even though all nanny's should be ignored at all costs and locked away somewhere the moment they appear on the lot)