BuddyPress.org

That’s a theming / presentational issue which you need to address through the CSS / markup.

In this case if you are referring to (Please be explicit about where you see issues) the space above the swf then you have an empty paragraph tag there for no reason; you need to remove that to close the gap.

As for the horizontal alignment I’m afraid you have a fixed width element in a fluid layout and will always have issue with narrower browser widths the fixed width now dictates the min-width you must set the site layout to work with.