Issues with Comments form

I’m having issues with a Leave a Reply/Comment form on my clients page. For starters, the submit button does not appear unless you tab down past the text area. Then you see it. But in reality, you should see it in the div. Secondly, there’s way too much of a gap between each text field / text area and I tried all sorts of margin styles in the style.css but to no avail. Lastly, submitting the page takes you to a 404 Not Found page and I can’t figure out why it’s redirecting to that page instead of a thank you page. The comments do go through for approval though.

Thre page in question is here. and any help would greatly be appreciated with all these changes in the TwentyEleven theme.