Checkbox State Help

Try to get the checkbox state into a var from an if Flash CS3 AS2.0
When I press a button I have set up to email I cannot seem to get the state of the checkbox working.
I can get a value but is always the same weather ticked or not. below code always returns no

Please can anyone help

on (release) {

if (this.RSVP_text_popup.Check_box.selected) {
var Coming = "Yes";
} else {
var Coming = "No";
}

var subject = "Wedding Invite "+GuestsNames.text+" "+Coming;
var body = _root.RSVP_text_popup.RSVP_bodycopy.body_Text.text;

getURL("mailto:jpanddt@ihug.co.nz"+"?subject="+subject+"&body="+body);

}