this.formToArray is failing to parse file object from form in ember

Question

I am using following part of code in ember

<form id="UserProfileForm" method="POST" enctype="multipart/form-data">
<input type="file" name="file" id="abc1">
<label>{{ view.fileName }}</label>
</form>

And I am using following code to submit file object to controller.

var settings = {
            dataType: 'text',
            target: '#response',                   // target element(s) to be updated with server response 
            success: function () {debugger},             // post-submit callback
            url: '/audio/upload',
            type: 'POST',
            error: function (e) {debugger}
        };
        $("#UserProfileForm").ajaxSubmit(settings);

But internally .ajaxSubmit using formToArray and its failing

Same part of code is working when I use it in JSP page.

Thanks in advance...