JQuery Form Plugin - Missed TypeError on file upload

Question

JQuery Form Plugin - Missed TypeError on file upload

there is no problem when I do not select any file to upload, when I just fill in other inputs besides the message form, it works. but when I select the file to upload the image than the post, I get this error, but when I look at the folder, I see that the file is loaded. but javascript failed.

jquery.form.js:357 Uncaught TypeError: Object function (a,b){return new d.fn.init(a,b,g)} has no method 'handleError'

here is my code

 <form id="employeeaddform" class = "classform" enctype="multipart/form-data" action="inc/employeeadd.php" method="post"> <p><input type="file" size="32" name="my_field" value="" /></p> <p class="button"><input type="hidden" name="action" value="image" /> <label for="nname">Personal Name : </label> <input name="nname" id="nname" type="text" tabindex="11" /> <br /> <label for="ninformation">Information : </label> <textarea id="ninformation" name="ninformation"></textarea> <div align="center"> <input id="button1" type="submit"/> <input id="button2" type="reset" /> </div> </form> <script type="text/javascript"> $(document).ready(function(){ var options_employeeadd = { beforeSubmit: validate_employeeadd, // pre-submit callback success: showResponse_employeeadd // post-submit callback }; $('#employeeaddform').ajaxForm(options_employeeadd); }); function validate_employeeadd(formData, jqForm, options) {...} function showResponse_employeeadd(responseText, statusText, xhr, $form) {...}