During the take off run on runway 34 the first oficer, who was flying the aircraft, called "failure" at approximately 120 knots. This was below V1 and the captain rejected the take-off. The Master Caution Air Conditioning lights were illuminated. The auxiliary power unit bleed air was supplying the left pack which was running in high mode. The pack tripped off as a result of high temperatures. Autobrake was used in the rejected take-off selection and operated until down to a slow speed in the deceleration. The outboard left main wheel tyre delaflated due to overheating. Both left main gear wheels and the left outboard brake unit were subsequently changed. Take-off should not be rejected from high speed for a Master Caution. However, when the first officer responded by calling "failure" the captain was obliged to reject the take-off. Significant Factors: 1. Master Caution Air Conditioning lights illuminated during the take off roll. 2. The first officer incorrectly called "failure" for the caution light illumination. 3. The captain was obliged to reject the take off on the basis of the first officers call.