This error means the Web Video Recorder does not detect the camera or capture device on your computer.
Make sure that the camera or capture device is connected directly to your PC and that it is powered on before starting the program. Also, check and make sure no other program on your computer is using the camera or camera resources, such as a built-in microphone.
Finally, check that you are using the latest software drivers from the camera's manufacturer.
Check all these settings, close the program, and then reopen it. It should detect the camera.
