I have a button which has probably been implemented wrong, since it causes an error 500. The page works fine without the button and I'm not sure where the problem lies.

The .aspx:

<asp:Content ID="Main" ContentPlaceHolderID="PlaceHolderMain" runat="server">
<div id="notify_form">
    <p>Please enter a new email:</p>
    <table class="ms-formtable" width="100%">
            <td><input type="text" runat="server" id="txtEmail"/></td>
            <td class="ms-formlabel"></td>
                <asp:Button runat="server" ID="btnSubmit" OnClick='SaveEmail' />
                <asp:Button runat="server" ID="btnCancel" OnClientClick="window.frameElement.cancelPopUp(); return false;"/>

The SaveEmail method does nothing at the moment.