Well, the repeat region is not inside a form. meaning that the checkboxes are not contained in a form, and there for cannot be submitted.
you need to have a form around the repeat region and a submit button to trigger the update.
this tutorial:
http://www.webassist.com/tutorials/Multiple-Updatable-Textfields---Results-Page
does match close to what you are trying to do, a multiple update form on a results page.
take a closer look at that one.