If you do not see the webcam picture but instead all you see is a white screen, please try the following: Sometimes other devices on your computer (other cameras, video cards, software) will show up as a camera source to Flash, and you need to specify which one is your active webcam.
Right-click your mouse on the white screen (where your webcam picture should appear) and click on "Settings".
Click on the "webcam" icon to bring up that tab and makes sure that your webcam is selected as the proper camera source.
Please make sure no other software like Yahoo, MSN, or other messenger/video applications are open, sometimes they can lock the camera so other programs (like Flash) can not access the webcam.
Please make sure you have the latest version of Flash player installed, re-install if necessary.
Please make sure that your webcam is properly installed. This means that in addition to physically connecting your webcam to your computer you must also install the proper drivers to make it work. Usually these drivers came on the CD with your webcam, but otherwise you can Google your webcam type and download drivers for free online.