Getting Issue with validation messages in mvc 3

Hi Experts,

If I have submitted the data with out any fire of error messages, its working fine, but once error messages fired and re entered the input fields as per validations. Its submitting the data but calling controller action method and model values becoming null that results to throw exception.
please see my code snippet below.

Kindly help me if any body having any idea about this issue.

$('#frmRegisterInvitedUsers').submit(function (e) {
if ($("#frmRegisterInvitedUsers").valid()) {
$.ajax({
url: this.action,
type: this.method,
data: $(this).serialize(),
success: function (result) {
showSuccessMessage(result);
}
});
}
e.preventDefault();
return false;
});

function showSuccessMessage(data) {
debugger;
if (data.s != '' && data.s != undefined) {
$("#divResult").html("<div class='popupMsg'>" + data.s + "</div><div style='float:right; margin-right:35px;'><input type='button' id='btn_confirmOK' name='btn_confirmOK' value='@LanguageManager.btnFullOnRegistrationOk' class='submitButton' style='width:100px;'/></div>");
$(".notification").height(50);
$('.notification').slideDown('fast');
$('.overlayHidden').show();
$('#btn_confirmOK').bind('click', function () {
alert('test');
$('.notification').slideUp('fast');
$('.overlayHidden').hide();
window.location.href = '../Home/Home';
});
}
}
Thanks
Prasad