jquery validate 1.9 plugin not working in IE7 and IE8

jquery validate 1.9 plugin not working in IE7 and IE8

 I've got the following code to validate a registration form.  In Firefox, Chrome or IE9,if the user tries to click the register button on an empty form the error messages show up fine.  In IE7 or 8 no error messages appear.

Here's the jquery:

    $('#form_register').validate({
    messages: {
    register_full_name: 'Please enter your name',
    register_email: {
    required: 'Please enter your email',
    email: 'Please enter a valid email address'
    },
    register_username: {
      required: 'Please choose a username',
      minlength: 'Make it at least 3 characters'
      },
    register_password: {
      required: 'Please choose a password',
      minlength: 'Make it at least 6 characters'
       },
    register_newsletter: {
      required: 'Please select either Yes or No'
       }
     },
    rules: {
      register_password: {
        required: true,
        minlength: 6
      },
      register_username: {
        minlength: 3
        }
       },
      submitHandler: function(){
       submit_register();
       return false;
       }
    });

This alert does not show in IE7 or IE8:

    $.validator.setDefaults({
      errorElement: 'span',
      errorPlacement: function(error, element){
        alert('$.validator.setDefaults');
        $(element.parent('label')).addClass('error');
        error.appendTo( element.parent('label') );
        },
        success: function(label){
        $(label.parent('label')).removeClass('error');
        }
    });