I bought JFK v2.1 yesterday and after installing it, I get a " Prear3d.exe stopped working" CTD when the sim is trying to load. I uninstalled JFK v2.1 and the problem goes away.
This is on a fresh install of P3d v3.4 HF2 and there are no other FSDT or Flightbeam airports installed. Addon Manager and Couatl are not installed either.