I guess part of my problem understanding your problem has been some communication difficulties... specifically, you talking about the check box, when what I see you really meant was the radio button. You see, square boxes that you put a checkmark into are called "check boxes", while round circles that you put a dot into are called "radio buttons" (don't ask me why it's called a "radio button" when it's not a button). Now see this creates a problem when you are talking about a check box, and the only check box related to this hack is the one that makes a thread a news item, so that's what I think you are talking about. Please understand, I don't mean this as an attack against you, I just mean this as helpful advice, to create better understanding.
You can send me a copy through email (do not attach it to a message here!) of your usergroup.php file to
webmaster@jjr512.com and I will see if I can figure out what's out of whack. Also, include in the email a copy of the structure of your usergroup table (just the structure, not the data!).
I'd still like to hear from anyone else that has installed this hack if they have or have not had this problem... I know some people have installed it, and since I'm not hearing any other complaints, I'm assuming it's working fine for everybody else; I just want to be sure.