Whitespace appears only on index page

For some reason I get an unexplained bit of space at the top of my index.php page, but not on any other pages. I’m including the same exact header.php file on all pages, yet the whitespace only shows up on index.php (regardless of whether I show posts or a static page, the whitespace is there).

I set my html and body margins to 0. When I reset all top margins to 0 the index.php page appears properly, but every other page appears to have a negative margin…

I can’t for the life of me figure out what’s going on. Any help is appreciated.

http://design.enricospada.com/frank/wordpress/