Integrating the RFD8500 into a C# app

Trying to get started with integrating the RFD8500 into a C# app. Add references, add using statements and then add : IRemoteReaderManagement readerManagement = RfidSdk.RemoteReaderManagementServicesFactory.Create(); to begin the very basic functionality of finding available devices. App compiles and runs, then throws an exception : "Value does not fall within the expected range." Not much I can figure as to why this is failing - error message isn't any help and the call disappears into an interface in a dll, so no way to investigate. The demo app works fine and connects as it should, so it's a very frustrating situation. Is there anyone who can point me in the right direction? Thank you in advance.