open up the shoutbox.php
find 
	PHP Code:
	
		
			
    if ($isloggedin!="yes") {
        $user = "Guest";
        }
    $comment = $comment;
    mysql_query("INSERT INTO ".$prefix."shoutbox VALUES ('', '$user', '$date', '$comment')");
    $article_content = $article_content."<p>Your comment has been posted. Click <a href='shoutbox.php'>here</a> to view it.</p>"; 
		
	
 I would suggest
	PHP Code:
	
		
			
    //if a user is logged in then allow them to post and let them know
    if ($isloggedin=="yes") {
    mysql_query("INSERT INTO ".$prefix."shoutbox VALUES ('', '$user', '$date', '$comment')");
    $article_content = $article_content."<p>Your comment has been posted. Click <a href='shoutbox.php'>here</a> to view it.</p>";
        }
     else{
    $article_content = $article_content."<p>You can not post with out logging in.</p>";
     } 
		
	
 And why does $comment = $comment; is just beyond me.....
EDIT:
oh, not that i am super concerned by this; This type of questions would better fit the Questions and Supports forum as it more of a technical issue.