Error: '1' is null or not an object in autocomplete


I am new in jquery and I have code for autocomplete, but now I encountered error : ‘1’ is null or not an object when I type letter that was not available in the database. I want to disappear that error. But I don’t have any idea how can I disappear that error when I type letter which is not available or did not match in the database. But if I type letter that match in the database no error display.

here is my code:



<script type="text/javascript" src="jquery.js"></script>
<script type='text/javascript' src='jquery.autocomplete.js'></script>
<link rel="stylesheet" type="text/css" href="jquery.autocomplete.css" />
<script type="text/javascript">
//----auto complete process name---//
$().ready(function() {
    $("#process_name").autocomplete("get_process_list.php", {
       width: 205,
        matchContains: true,
        mustMatch: true,
        selectFirst: false

    $("#process_name").result(function(event, data, formatted) {

<td><input type="text" name="process_name" id="process_name" value="" size="30"></td>
<input type="hidden" name="process_id" id="process_id" value="" />

Any help is highly appreciated.

Thank you