Try Steve Main's response here (3rd down):

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=373333&SiteID=1

I found it not long ago when I was playing around with the sample stuff - trying to figure it out and just making a mess :o)

oh, and this:

http://www.robzelt.com/blog/2007/01/24/WCF+This+Collection+Already+Contains+An+Address+With+Scheme+Http.aspx


>Hi All,
>
>I am trying to get a WCF service to run on my hosted site. I have it working locally on my development machine but when I publish it to a subdirectory under our website host we get an error. The directory where I am publishing it has been marked as virtual (application root).
>
>

>Source Error:
>
>An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
>
>Stack Trace:
>
>[ArgumentException: This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection.
>Parameter name: item]
>   System.ServiceModel.UriSchemeKeyedCollection.InsertItem(Int32 index, Uri item) +4564833
>   System.Collections.Generic.SynchronizedCollection`1.Add(T item) +56
>   System.ServiceModel.UriSchemeKeyedCollection..ctor(Uri[] addresses) +120
>   System.ServiceModel.ServiceHost..ctor(Type serviceType, Uri[] baseAddresses) +145
>   System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(Type serviceType, Uri[] baseAddresses) +28
>   System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(String constructorString, Uri[] baseAddresses) +323
>   System.ServiceModel.HostingManager.CreateService(String normalizedVirtualPath) +516
>   System.ServiceModel.HostingManager.ActivateService(String normalizedVirtualPath) +31
>   System.ServiceModel.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath) +498
>
>[ServiceActivationException: The service '/Tracker/Tracker.svc' cannot be activated due to an exception during compilation.  The exception message is: This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection.
>Parameter name: item.]
>   System.ServiceModel.AsyncResult.End(IAsyncResult result) +4413209
>   System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result) +183
>   System.ServiceModel.Activation.HostedHttpRequestAsyncResult.ExecuteSynchronous(HttpApplication context, Boolean flowContext) +205
>   System.ServiceModel.Activation.HttpModule.ProcessRequest(Object sender, EventArgs e) +322
>   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +92
>   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64
>

>
>I am so not an IIS guy and could really use some direction on sorting out this error.
>Thanks
>Tim