Other mistake: In the scene when the helicopters arrive over the research center, look at the heli in the bottom right - it just fades out, while one on the left materialises, and the one in the middle changes position. Notice that after all the helicopters have changed place, you can see the helicopter that faded out appear on the helipad. (02:25:25)
Other mistake: When Gregory Peck was being zoomed in on there are several fresh horse tracks.
Other mistake: The split second that a running student passes in front of her, Miss Mackay calls her name and restrains her, reacting much faster than humanly possible. (00:02:50)