Silverlight 4 Async_ExceptionOccurred

I've been developing a Silverlight 4 wb application w/ WCF service on my laptop (visual studio 2010). Everything works as expected.

Now i'm trying to "deploy" to a test environment (windows server 2003, ii6, dotnet4).

The WCF service is working AOK (i installed wcfstorm and can connect and interact with it).

The Silverlight web application is loading but not interacting with the service. I'm seeing the following error:

Uncaught Error: Unhandled Error in Silverlight Application [Async_ExceptionOccurred] Arguments: Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=4.0.50524.0&File=System.dll&Key=Async_ExceptionOccurred at System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary() at adDEPOT_Invoice_Emailer.aIE.getInvoiceListCompletedEventArgs.get_Result() at adDEPOT_Invoice_Emailer.MainPage.adDEPOT_IE_getInvoiceListCompleted(Object sender, getInvoiceListCompletedEventArgs e) at adDEPOT_Invoice_Emailer.aIE.adDEPOT_IEClient.OngetInvoiceListCompleted(Object state)
 
I don't believe it's a crossdomain/policy issue as the web app and service reside on the same domain/port. I've create the xml files anyway just in case!

Any ideas?

Thanks