hello,
if i've understand, you have a screen whith powerpoint, can you say me the duration time of him? and the duration of flash and video?
if you want your powepoint play 30 min, you put your time end to 00:30:00 and you make it for your flash and video.
in your schedule, you put your time bloc to 120 min and put your powerpoint; your flash, your video. it will play first powerpoint during 30 min, flash during 30 min, and finally video during 30 min. reduce your end zone for play all more time... you must extend your time zone at all the day for play your 3 screens on the day.
have you try to push only your video? did it play? and your flash only?
if they don't play perhaps you haven't the player software installed like codec or flash player
i hope have help you.
say me if i've help you or if you've more help
excuse me for my broken english, i'm french...