B757 Captain reports rejecting takeoff for cabin door message at around 100 knots.

Narrative

This was day three of a 6-day trip for the Captain; the first leg of a 3-day trip to ZZZZ as a crew. A normal departure briefing was conducted with the highest threat stated as the crew's first flight together; flying the B757 (normally B767ER) and taxi challenges present at JFK. Standard abort criteria over 80 KTS was briefed; fire; engine failure; unable or unsafe to fly. After an hour of taxiing the aircraft was cleared for takeoff full length on Runway 31L. Winds were estimated 330 at 20+ KTS. Temperature was estimated at -2C. Runway was dry. At around 100 KTS; I rejected the takeoff for an EICAS right Aft Entry Door message. The First Officer notified the Tower that the takeoff was being discontinued; I made a PA to the passengers. Aircraft control was normal and the aircraft was taxied off the runway at about the mid-point. Doors and brakes were checked and a decision was made to taxi to the parking stand. The Quick Reference Handbook was reviewed for post abort procedures. Brake indications were checked with readings mainly 1 and 2. At the parking stand; Maintenance completed a high energy brake check. Mechanics found a door sensor out of tolerance and the item was deferred. After a telephone call to Operations the crew received approval from the Duty Pilot and Chief Pilot to continue the flight. Perceptions; judgments; decisions: Normal temporal cues were accelerated on this takeoff because of increased performance due to light weight; significant headwinds and low temperatures; giving the perception that we were significantly early in the takeoff roll when we had the door message. The decision to abort; I considered it unsafe to continue the takeoff based on the EICAS message; Right Aft Entry Door. The added safety margin of a long 14;572 FT runway; with a significant headwind and sub-zero temperatures were contributing considerations. I believe that the quality of simulator training for the abort event prepared the crew to perform effectively. Given that this was the first leg of this crew pairing; crew coordination in this evolution was smooth and efficient.