I'm thinking that you are talking about testing the site in your browser.

Check your publish settings for the size problem. You can set it match the movie's dimentions, fit to a percentage of the browser window, or set specific dimentions other than what the movie is created as.

The purple outline is probably the background color of your project. Browsers add a border around the embedded SWF. You can either change the color or get rid of the borders. The first can be done in Flash itself or by editing the HTML. The second requires editing the HTML.