You say that Aperture is up to date but what about your OS? Is that at the latest verrsion also? That camera was supported starting in Digital Camera Raw update 4.06.
Assming your OS is up to date what message are you getting when you try to import the files from the camera?
BTW what OS version are you running?
Thx Frank for pointing this obvious thing out. I reinstalled my Lion Mac Pro from scratch and assumed it was up to date (as this is what th eOS reported to me), but it was because you pointen out that release 4.0.6 was needed for D7100 support that i intalled it manually. Reporcessed the NEF files without a problem.