I finally got my webcam to work on skype (sort of). I have a Logitech QuickCam Messenger (046d:08da), which is a v4l2 (video4linux v2) device. Skype only (still) works with v4l version 1. Thus “Houston, we’ve got a problem”!
I almost solved the puzzle.
Today I got another Windows Vista update error: 800F0902.
Luckily I found a useful post @ http://itsvista.com/2008/01/windows-vista-sp1-rc-refresh-available-to-public/ [31] that proposed to change some stuff in the registry.