Welcome to the forum.
Can you provide us with more information, please?
This FAQ Entry will direct you, as to what info would be most useful: http://forums.adobe.com/thread/961741?tstart=0
As well as what Hunt suggested, video information would be good
Codec & Format information, with 2 links inside to read
-read both links in reply #1 http://forums.adobe.com/thread/1270588
Report back with the codec details of your file, use the programs below... A screen shot works well to SHOW people what you are doing