New Post: Cannot add a data type since it will cause some compilation erros!

I am getting an error when trying to add a new Global DataType and add data to either an existing global datatype. The error is:

Cannot add a data type since it will cause some compilation errors.(File name: 's:\TECS\Website\App_Code\Startup.cs', line: 12, column: 31, message: The type or namespace name 'IAppBuilder' could not be found (are you missing a using directive or an assembly reference?))

I have all the necessary assemblies installed and everything else works as expected. The only issue I have found is the issue with the global datatypes. Any suggestions on how to resolve this?

Thanks for your help. I am stuck at this point.
Rob


Startup.cs

using System;
using System.Threading.Tasks;
using Microsoft.AspNet.Identity;
using Microsoft.Owin.Security.Cookies;
using Microsoft.Owin;
using Owin;

[assembly: OwinStartup(typeof(Startup))]

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=316888
        app.UseCookieAuthentication(new CookieAuthenticationOptions
        {
            AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
            LoginPath = new PathString("/account/Login.aspx")
        });
    }
}