Debugging Web to Lead forms in ASP.NET

Good morning,

I'm trying to implement a Zoho Web to Lead form in ASP.NET 4.0. Has anyone accomplished this?

When https://crm.zoho.com/crm/WebToLeadForm opens, I simply get a blank page. No error messages, nothing.

Here's a snip-it of the core code:
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">
    <asp:HiddenField ID="xnQsjsdp" Value="i8USzv*O5vs$" runat="server" />
    <asp:HiddenField ID="xmIwtLD" Value="NG4SH0R7m7dn4wxS4ZbUZc8TG*oHI*WT" runat="server" />
    <asp:HiddenField ID="actionType" Value="TGVhZHM=" runat="server" />
    <asp:HiddenField ID="returnURL" Value="http://www.soundequityinc.com/default.aspx" runat="server" />

    <div id='crmWebToEntityForm' align='left'>

                        <td><asp:TextBox name="First Name" maxlength='40' size="25" runat="server"></asp:TextBox></td>
                        <td><asp:TextBox name="Last Name" maxlength='80' size="25" runat="server"></asp:TextBox></td>

                <asp:Button ID="btnSave" runat="server" PostBackUrl="https://crm.zoho.com/crm/WebToLeadForm" Text="Submit" />
    </div>

</asp:Content>