WsDualHttpBinding Problem

[dnanetwork]

AdaPost Any Help!

This is my Server Side Code..
IIS 7 at Server

Interface Code

[ServiceContract(SessionMode=SessionMode.Allowed,CallbackContract= typeof(interfaceDuplexCallBack))]
    public interface IDuplexService
    {
        [OperationContract(IsOneWay=true)]
        void DoWork();
    }

    public interface interfaceDuplexCallBack
    {
        [OperationContract(IsOneWay = true)]
        void Done();
    }

// Interface Implemetation

public class DuplexService : IDuplexService
    {
        public void DoWork()
        {
            Console.WriteLine("Called By Client at First Time " + DateTime.Now.ToString());
            Thread.Sleep(5000);
            Console.WriteLine("Work Done at " + DateTime.Now.ToString());
            OperationContext.Current.GetCallbackChannel<interfaceDuplexCallBack>().Done();
        }

        
    }

//Server Side Web.config Settings

<service behaviorConfiguration="DuplexService.DuplexServiceBehavior"
        name="DuplexService.DuplexService">
        <endpoint address="http://10.25.1.202:8089/DuplexService/DuplexService.svc" binding="wsDualHttpBinding" 
                  contract="DuplexService.IDuplexService">
        </endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
      </service>

On Client Side
IIS 6.

// Client Side Web.config Settings

<bindings>
   <wsDualHttpBinding>
    <binding name="WSDualHttpBinding_IDuplexService" closeTimeout="00:01:00"
     openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
     bypassProxyOnLocal="false" transactionFlow="false" hostNameComparisonMode="StrongWildcard"
     maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text"
     textEncoding="utf-8" useDefaultWebProxy="true" [B]clientBaseAddress="http://localhost/WebApplication"[/B] >
     <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
      maxBytesPerRead="4096" maxNameTableCharCount="16384" />
     <reliableSession ordered="true" inactivityTimeout="00:10:00" />
     <security mode="None">
      <message clientCredentialType="None" negotiateServiceCredential="true"
       algorithmSuite="Default" />
     </security>
    </binding>
   </wsDualHttpBinding>
  </bindings>
  <client>
   <endpoint address="http://10.25.1.202:8089/DuplexService/DuplexService.svc"
    binding="wsDualHttpBinding" bindingConfiguration="WSDualHttpBinding_IDuplexService"
    contract="MyService.IDuplexService" name="WSDualHttpBinding_IDuplexService">
    <identity>
     <servicePrincipalName value="host/10.25.1.202" />
    </identity>
   </endpoint>
  </client>

Error :

HTTP could not register URL http://+:80/Temporary_Listen_Addresses/3562955b-d57e-4651-8a66-9bd5f7913b83/ because TCP port 80 is being used by another application.

why am i getting this error..

am i using the wrong version of IIS at client side ?

am i missing something..?