It needs to be in the Form tag.  This is how it should look, it will need further formatting but it works.

 

<form id="form1" runat="server">
    <div id="navtop">
        <asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" ShowStartingNode="false" />
        <asp:Menu ID="TopNavMenu" Orientation=Horizontal runat="server" DataSourceID="SiteMapDataSource1">
        </asp:Menu>
    </div>
        <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
        </asp:ContentPlaceHolder>
       <div id="navbottom">
       <asp:Menu ID="Menu1" Orientation=Horizontal runat="server" DataSourceID="SiteMapDataSource1">
       </asp:Menu>
    </div>
    </form>