I'm fairly new to web design, and having a simple problem.

On many sites, there is a horizontal bar that extends from left to
right. Usually designers place nav buttons there.
Well it covers the screen no matter what size the browser is. When I
rescale the browser window, the bar accomodates automatically.

The site Im building has a nav bar like this:


The black strip is limited to the size of the swf file. How do I make
the bar autoscaling? Is it Flash, or other code type?