Apologies for the late reply - I thought I had email notifications turned on for this board but apparently not.
I used Visual Studio -> Tools -> Error Lookup to look up the error id and got this:
-2146893016: The received certificate has expired.
The problem is that the demo certificates in RCFProto 0.9.0.4 have expired. I've generated new ones (this time with 10 years validity) , for 0.9.0.5 which you can download from the Downloads page: