Update Panel

Hi all, looking for some ideas on this one.

I have an update panel that displays users as someone types in their name. This triggers the update panel. On my local server it works fine, on a web server we have somewhere in this country it works fine, but when deployed to a clients server in China the update progress fires but the update panel doesn't update.

Some code for reference:

<div id="ResultsDiv"><script language="javascript" type="text/javascript">
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    function CancelAsyncPostBack() {
        if (prm.get_isInAsyncPostBack()) {
            prm.abortPostBack();
        }
    }

    prm.add_initializeRequest(InitializeRequest);
    prm.add_endRequest(EndRequest);
    var postBackElement;
    function InitializeRequest(sender, args) {
        if (prm.get_isInAsyncPostBack()) {
            args.set_cancel(true);
        }
        postBackElement = args.get_postBackElement();
            $get('<%= PageUpdateProgress.ClientID %>').style.display = 'block';
            $get('<%= UpdatePanel1.ClientID %>').style.display = 'none';
    }
    function EndRequest(sender, args) {
            $get('<%= PageUpdateProgress.ClientID %>').style.display = 'none';
            $get('<%= UpdatePanel1.ClientID %>').style.display = 'block';
    }</script><asp:UpdateProgress runat="server" id="PageUpdateProgress"><ProgressTemplate><div style="text-align:center;"><img src="../Images/ajax-loader.gif" alt="Loading" /></div></ProgressTemplate></asp:UpdateProgress><asp:UpdatePanel ID="UpdatePanel1" runat="server"><ContentTemplate><asp:Panel ID="Panel1" runat="server"></asp:Panel></ContentTemplate><Triggers><asp:AsyncPostBackTrigger ControlID="FirstNameTxt" EventName="TextChanged" /><asp:AsyncPostBackTrigger ControlID="UserNameTxt" EventName="TextChanged" /></Triggers></asp:UpdatePanel></div>