Have you tried updating the widget? The latest version worked for me.
Seems like a null pointer exception, have you checked the datasource?
Tracy
Not sure if there are other custom widgets on this page. If so, in the past I have found conflicts between widgets. The quickest way I’ve found to see if this is the case is to put just the checkbox widget on a vanilla page and see if the error occurs. If not, there is a widget conflict of some sort. To identify which widget is the causing the issue, I will create a backup copy of the page for safekeeping. Then remove all of the widgets except the checkbox widget and, one by one, copy and past the widgets back onto your page from the backup. Its a bit painstaking, but I figured it might help you narrow down the issue you’re having.
Mike