Distance to image with keying goes black at end

TEXT REVEAL INTRO I have set track matt key and image is good. It is on correct video layer. I have text on 3d setting and when i go to set distance to image i start with two seconds into video but dont set stop watch.. Then i jump a few frames and set stop watch and set to -100. When the video goes it works until the end and goes to all black. Whats weird is it works sometimes and other times it wont. And i do the same settings. Thanks Help please