“No Capture could be found or the VDIG is not installed correctly”

You have to install quicktime and a compatible video digitizer. Here are the links to download the last version of quicktime, and the WinVDIG 1.0.1 (recommended). Restart your computer after installation process and the webcam should work.

Recommended links:

http://processing.disenoudd.cl/tips/conectar-mi-webcam-a-processing-en-windows
http://www.eden.net.nz/7/20071008