Exception of type 'System.Web.HttpUnhandledException' was thrown when adding a menu to a sub page

I've added a new menu to my child page that is under the Site.Master where there is already an asp:Menu item.
I've already tried adding a runat="server" to the head tag of my Site.Master page and it allows it to run when I debug it fine,  but when I publish the site out to my server it shows up again  there????