Unable to Render Page with CheckBox on Gridview

On my web page, I have a gridview on a panel. I use a template field to add a checkbox to the gridview. Nothing on my page renders when I execute the application ... not even other controls on the page. If I remove the template field containing the checkbox, everything on the page renders successfully. I can also get it to render if I remove AutoPostBack="true" for the checkbox.
HTML for the panel is listed below. Any ideas?
<asp:Panel ID="pnlAgentList"
    runat="server"
    Height="300px"
    Width="250px"
    ScrollBars="Vertical">
    <asp:GridView ID="gvAgentList"
        runat="server"
        AllowSorting="True"
        Height="290px"
        Width="250px"
     &nbs ...