Replace your current code with:
PHP Code:
$article_content = $article_content."YOUR CHAT CODE HERE";
Paste the chat code where I have put YOUR CHAT CODE HERE. Before you paste in the chat code though paste it in a new notepad window, then do a find and replace and replace all " with ' so that the double quotes in the chat code are replaced with single quotes.
That may work and should show the shoutbox at the bottom of the page after the index page content. :)