Are you Windows or Mac?
What version of Quicktime do you have installed?
EXACTLY what is inside the video file?
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037
What is a CODEC... a Primer http://forums.adobe.com/thread/546811
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037
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
For future reference, please always start a message with the following information
Information FAQ http://forums.adobe.com/message/4200840