One thing I would do is replace:
var form = document.getElementById("form_opt");
var form = document.forms["form_opt"];
Check to make sure the error isn't in your "sort_and_unique()", "checkRadio()", or "getSelectedButton()" functions.
I'm not sure what this is supposed to do, but it looks like it's concerning every radio button within a particular form.
If anyone knows of a website that can offer ColdFusion help that isn't controlled by neurotic, pedantic jerks* (stackoverflow.com), please PM me with a link.
* The neurotic, pedantic jerks are not the owners; just the people who are in control of the "popularity contest".