Patience
You need to convert the sonic sprite to a GIF file and use your picture editor's Magic Wand tool to delete the white before importing it into flash.
My other problem is when the movie is finnished it returns to the start and the music starts laying again resulting in two tracks playing at once (which sounds terrible). At the end of the movie you need to stop the sound so when the movie starts again only one sound is playing
However a 7 for your patience and effort.