Type or namespace name XrmServiceContext could not be found

Type or namespace name XrmServiceContext could not be found (are you missing a using directive or assembly reference?)

I am building a portal to connect to CRM 2011 and I am using this http://msdn.microsoft.com/en-us/library/gg695790.aspx

 tutorial. But I am getting the following error when I try to follow the last part of the tutorial"Create another webpage-contact grid 3"

Here is the screenshot of the error I get