I know this has happened before with other users, but schoolsucks779 has something weird going on with his sig that can prevent a user from replying to a thread he has posted in, or seeing posts beneath his. A simple workaround for this and other sig problems is to place said user on your ignore list (there's an 'ignore' button along the top of every post). That way you can read his post in a separate window by clicking on it, and you are still able to reply to the thread and read other replies.