UriException is Unhandled Invalid URI: A port was expected because of there is a colon (':') present but the port could not be parsed.

I am using VS2008 and I am trying to complete a tutorial found at http://community.opennetcf.com/blogs/cf/200711/WCF/An%20Introduction%20to%20WCF%20for%20Device%20Developers.pdf. I am however stuck halfway as I get a debug error :-
UriException is Unhandled Invalid URI: A port was expected because of there is a colon (':') present but the port could not be parsed.

This occurs after the declaration of a formatted string to a URI. Below is the code that I am using. What should I do to get around this?

using System;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.Net;
namespace OpenNETCF.WCF.Sample
{
    class Server
    {
        static void Main(string[] args)
        {
            string hostIP = Dns.GetHostEntry(Dns.GetHostName()).AddressList[0].ToString();
#if CLIENT_DISCOVERY_BUILD
Uri address = new Uri(string.Format("http://localhost:8000/calculator", hostIP));
#else
            Uri address = new Uri(string.Format("http://{0}:8000/calculator", hostIP));  //THE EXCEPTION IS BEING THROWN HERE
#endif
            ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), address);
            try
            {
                // Add a service endpoint
                serviceHost.AddServiceEndpoint(typeof(ICalculator),new BasicHttpBinding(),"Calculator");
#if CLIENT_DISCOVERY_BUILD
// Enable metadata exchange
// this is needed for NetCfSvcUtil to discover us
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
serviceHost.Description.Behaviors.Add(smb);
#endif
                serviceHost.Open();
                Console.WriteLine(
                "CalculatorService is running at " + address.ToString());
                Console.WriteLine("Press <ENTER> to terminate");
                Console.ReadLine();
                // Close the ServiceHostBase to shutdown the service.
                serviceHost.Close();
            }
            catch (CommunicationException ce)
            {
                Console.WriteLine("An exception occured: {0}", ce.Message);
                serviceHost.Abort();
            }
        }
    }
}