I am validating a group of checkboxes - and it works in jquery.validate.js v1.13.0 - but when I updated to v1.13.1, the checkboxes no longer validate. Any help would be appreciated

Here is my js ...

1.     $('#reg').validate({
2.         rules: {
3.             'titlechoices[]': {required: true, minlength: 1},
4.         },
6.         messages: { 'titlechoices[]': { minlength: 'Please select at least {0} options' } },
8.        errorPlacement: function (error, element) {
9.            if(element.attr("name") == "titlechoices[]"){
10.       error.appendTo('.TitleError');
11.                } else {
12.                error.insertAfter(element);
13.               }
14.       }
15.     });

And the relevant html...

1. <fieldset>
2. <input name="titlechoices[]" type="checkbox"  class="check_txtbx"  value="BA">&nbsp;BA
3. <input name="titlechoices[]"  type="checkbox"  class="check_txtbx" value="BS">&nbsp;BS
4. <input name="titlechoices[]"  type="checkbox"  class="check_txtbx"  value="CNM">&nbsp;CNM
5. <input name="titlechoices[]"  type="checkbox"  class="check_txtbx"  value="CRNA">&nbsp;CRNA
6. </fieldset>