First check: have you tried the demo site
demo.easyrtc.com to see if they work for you?
Are you using a webrtc supporting browser (chrome/firefox/opera)?
Have you tried hooking a webcam onto your laptop to see if its a browser problem or a built-in camera problem?
The most common problem is that the user didn't give the browser permission to use the camera/microphone once for your site, and the browser remembers this.
On the righthand side of your browser's URL bar, there will be a camera icon. If the camera is disallowed, it will have a red bar through it, which you can then click to allow the camera.