Importing Video Content - Help!

Hi,

Would someone be kind enough to assist me in importing video content? After optimizing a video clip in Handbrake, I convert, and import it as an .mp4 into Flash. Then, I convert the clip into .flv file format in Flash. However, upon testing, it will not play. It stays on initial frame of video. I don’t know what to do. Thank you anyone for your time and attention in helping me out with this. I’m using Flash CS5.