This must be concerning the scene where Mohammad Atta's named popped up on a ticket agent's screen as a "warning" and was let on anyway...only "holding" their luggage till the hijackers boarded the plane.
I just rewatched the scene at ABC http://pathto911.abc.com/index.html
(they've posted the movie online)
and it said "Selected Passenger Ensure-Hold baggage to be screened CAPPS warning" on the computer in the scene. I did an internet search and found this info at DHS.
http://www.dhs.gov/dhspublic/display?content=1115