I ended up disabling comments so that I can share the blog. (Just letting you know in case anyone heads to the site to see the problem)

I've been trying to set up my blog at http://formulac.eulercode.com/blog/ . But hitting submit or preview on the comment form just takes me back to the blog with a URL something like this: http://formulac.eulercode.com/blog/blog.php?serendipity[entry_id]=4&serendipity[name]=asdf&serendipity[...