Framerate issues with CS3

I have written a game in Flash CS3 using ActionScript 2. My target framerate is 30fps. When I publish the game from Flash and run the .html file provided it runs pretty well fine (btw, can someone explain what the additional javascript file is for - I think it’s just a version checker but why won’t the .swf run without it?).

Anyway, here’s my problem: if I import the .swf into a Dreamweaver site and then test that out, the framerate is a lot slower, even if the Dreamweaver site has no content at all. Can anyone explain why and give me a good solution?

Thanks a lot