File Uploading Problem When I Uploaded In Iis 7 And Window Server 2008 R2

page load:
if (ViewState["attachemnet1"] == null && flupEmailAttachment.HasFile)
{
ViewState["attachemnet1"] = flupEmailAttachment.FileName;
lblAttachemnt1.Text = flupEmailAttachment.FileName;
}
// Next time submit and Session has values but FileUpload is Blank
// Return the values from session to FileUpload
else if (ViewState["attachemnet1"] != null && (!flupEmailAttachment.HasFile))
{
lblAttachemnt1.Text = ViewState["attachemnet1"].ToString();
}
// Now there could be another sictution when Session has File but user want to change the file
// In this case we have to change the file in session object
else if (flupEmailAttachment.HasFile)
{
ViewState["attachemnet1"] = flupEmailAttachment.FileName;
lblAttachemnt1.Text = flupEmailAttachment.FileName;
}


button click

protected void btnSendEmail_Click(object sender, EventArgs e)
{

if (ViewState["attachemnet1"] != null)
{

lblAttachemnt1.Text = ViewState["attachemnet1"].ToString();


}


javascripts design page:
<script type="text/javascript">
window.pressed = function () {
var a = document.getElementById('flupEmailAttachment')
if (a.value == "") {

lblAttachemnt1.innerHTML = "Choose file";

}
else {

var theSplit = a.value.split('\\');
lblAttachemnt1.innerHTML = theSplit[theSplit.length - 1];
}

}
</script>


<asp:Label Id="lblAttachemnt1" runat="server"><asp:FileUpload ID="flupEmailAttachment" onchange="pressed()" style="color: transparent" runat="server" /><input type="button"
title="+" runat="server" id="btnAddMoreAttachment_1" value="+" />


}

i have 3 model popup for showing message box but i am saving in the viewstate
then why i unable to save in the label and in the label file name is not displaying name