I’m pretty new to WP and am having trouble with my footer. It seems that the <?php get_footer(); ?> command plops the footer just underneath the sidebar and not under the actual page content. So my footer is floating in the middle of my page. This command is the very last line of index.php.
While you are using the WordPress default theme it looks like you have made some fairly significant modifications to the files and style. I suspect these changes is where the CSS and validation errors are coming from.