are the video and audio files compiled with the fla file? if so:
throw them out of there!! 
. You have to use a preloader to load the audio/video file into your swf from your server (ways faster and performance enhancing)
Splitting the swf into separate parts might (not sure though) also help (you can include swfs into other ones). The advantage of this is that each swf will load the contents into itself (audio/video files) while it is loading into the "main" swf