custom FaultException in Wcf give probelm============

Question

in FaultException We are getting "The creator of this fault did not specify a Reason."

my Service :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.Runtime.Serialization;

namespace InterFac
{

    [ServiceContract]
    //[ServiceBehavior (InstanceContextMode=InstanceContextMode.PerCall,
    //             ConcurrencyMode = ConcurrencyMode.Multiple)]
    public interface ISum
    {

        [OperationContract]
        Int32 sum(Int32 a, Int32 b);
        [OperationContract]
        string GetSlect();
        [OperationContract]
        [FaultContract(typeof(CustomException))]
        string GetMessage();
    }
}
[DataContract]
public class CustomException
{
    [DataMember]
    public string Problemdesc
    {
        get;
        set;
    }
    [DataMember]
    public string Hlink
    {
        get;
        set;
    }

}

===============Definition of GetMessage for Creating the Ex===============
 public string GetMessage()
        {
            try
            {
                int i, j, k;
                j = 1;
                k = 0;
                i = j / k;

            }
            catch (Exception exp)
            {
                CustomException obj = new CustomException();
                obj.Problemdesc = exp.Message;
                obj.Hlink = "http://www.Microsoft.com";
           
                FaultException<CustomException> o = new FaultException<CustomException>(obj);
                throw o;
                //throw new FaultException(exp.Message);
            }
            return "No Error";
        }

========Client Code where service is Calling ==============================



 SumClient client = new SumClient();      
        Response.Write(client.sum(5, 3));
        try
        {
             Response.Write( client.GetMessage());
        }
        catch (FaultException<CustomException> ex)
        {
            Response.Write(ex.Detail.Problemdesc + "<br/>" + ex.Detail.Hlink);

        }