I have both your JFK and ORD sceneries. Yesterday I finally got FSX reinstalled after a fairly large PC upgrade. I reactivated both sceneries like normal. But at JFK, about 5 minutes later, all the scenery vanished (except the gates and signage), almost like it was in trial mode. I have addon manager running and I used that to activate right in FSX.
What might be the issue?
Win7 x64 SP1, UAC off, no anti virus yet installed.
FSX Acceleration
edit: I've also looked through this thread:
http://www.fsdreamteam.com/forum/index.php?topic=4171.0