How to define namespace for imported project

How to define namespace for imported project

I'm getting really stuck trying to refer to methods in a project imported
into a blank project. The exact steps to recreate this are as follows
Download and Extract into a temp folder http://mywsat.codeplex.com/
Create a new project in VS - Asp.Net Empty Web Application .NET 3.5 named
WebApplication1
Copy all files from MYWSAT35 folder across to the new project
In VS solution explorer, select Show all files
If you now build and run the project runs fine with no errors.
5 In VS solution explorer, for all of the imported files right click and
select Include in Project
Now try rebuilding the project I get the error
The type or namespace name 'GetAdminMasterPage' could not be found
(are you missing a using directive or an assembly reference?)
GetAdminMasterPage.cs is located in
WebApplication1\App_Code\class\GetAdminMasterPage.cs and looks like this
#region using references
using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.Caching;
using System.Web.UI;