no need for answer unless you feel you want to contribute :)
So I feel stupid as hell I been banging my head against a wall with this for an hour... but for the sake of your head ill explain the problem, I had a mark-up that looks like this
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="MainSearch.aspx.cs" Inherits="MainSearchNewDesign" %>
And code behind that looks like this :
public partial class MainSearchNewDesign : System.Web.UI.Page
And still I got that damn error, the reason for that is that I forgot that if I have the a different file ( with a different name ) with the same class name the compiler still takes into account and tells you to go bang your head onto the wall...
Man I feel really stupid now... but I hope this will help someone.