Find all checkboxes with the same name, then ensure one radio is selected

Find all checkboxes with the same name, then ensure one radio is selected

Hi all. I have a range of radio buttons in a form. I need to have jQuery check that a radio is selected for each group and add a class to the label associated if not.

I thought this would work, but am having issues. I have checked and the name of the group is correctly added to the variable 'radio'. Any ideas?
  1.         $('.checkbox', this).each(function(){
                var radio = $(this).attr("name");
                if ($('input[name='+ radio +']:checked').length) {
                    $('label[for=' + radio + ']').addClass('error_label');
                    required = false;
                } else {
                    $('label[for=' + radio + ']').removeClass('error_label');
                }
            });