You are receiving a No Sources Found error message when connecting via 3G, but everything works as expected via WiFi? Are you ever receiving a Source Connection Error when attempting to connect via 3G?
The No Sources Found error message usually indicates that the login and password combinations do not match or that the iCamSource cannot communicate with the iCam Broker Server. If you are able to connect via WiFi then it doesn't make sense that you would be seeing the No Sources Found over 3G if using the same iPhone.