Jackson discarded the ball before he crossed the goal line on what was initially ruled a 61-yard touchdown. After a Cowboys' challenge and some incriminating evidence, the Eagles retained possession on the 1-yard line.
Brian Westbrook ran it in on the next play, so in the big picture this brain cramp won't have an impact on the final outcome. But Jackson should get used to seeing the clip for the rest of his career. If he has any questions, I'm sure Leon Lett could help him out.