Uploadify http error 500
<form id="myform" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="updateImg" runat="server">
<ContentTemplate>
<table width="100%" border="0" cellspacing="0" cellpadding="0" class="tb_3" style="margin-top:8px;
margin-bottom: 8px; height: 100%;">
<tr>
<td valign="top">
<table width="100%" border="0" align="center" cellpadding="0" cellspacing="2" class="table1">
<tr> <td class="style2">
<table style="width: 100%">
<tr>
<td style="width: 73%">
<div style="height: 270px; overflow-x: auto; overflow-y: auto; border: solid #A4B2BD 1px;
padding: 0px; margin: 0px; text-align: center;">
<asp:Repeater ID="Repeater1" runat="server">
<HeaderTemplate>
<table width="100%">
<tr><td align="left" style="width:30%">
物证名称
</td>
<td align="left" style="width:50%">
</td><td width="15%">
选择图片
</td> <td width="5%"> /td> </tr>
</table>
<hr />
</HeaderTemplate>
<ItemTemplate>
<table width="100%">
<tr style=" cursor:pointer" >
<script type="text/javascript">
$(document).ready(function () {
$('#<%# Eval("ID")%>').uploadify({
'uploader': '../../scripts/jquery.uploadify-v2.1.4/uploadify.allglyphs.swf',
'script': 'UploadHandler.ashx?id=<%# Eval("ID"