Flash video does not display when previewing the page

I encountered the following problem when I tried to implement a video clip into
an HTML page. I converted the mpg file into an FLV using flash video encoder
then I went to dreamweaver Insert > Media > Flash Video, I saved the document
and tried to preview it and nothing happened. I tried to encode the video again
(this time I set it up to an earlier flash player version just in case) and
still nothing.