Whenever /wordpress/wp-admin/post.php is hit, I see an error for /wordpress/wp-includes/js/tinymce/themes/advanced/\
images/opacity.png being missing (aka HTTP 404).
This is occurring with themes Spring 0.3beta by iqwolf, and veryplaintxt 2.0 by Scott Allan Wallick. Those are the only two I'm using right now, so I suspect it's not theme-related.
I'm running WordPress 2.02.