Suddenly my desktop computer couldn't grab audio when grabbing video!!! I spent 5 hours on this problem yesterday. I could grab audio just fine but it I started grabbing video (e.g. via amcap) audio grabbing stopped working. The audio device was a USB soundcard from Philips called Aurilium and the video device was a Logitech Orbit. Both are USB2.0 devices so I first thought that was the problem. I started moving around cables and reinstalling drivers. No luck. Next step was to exchange the Aurilium for a Creative Extigy USB soundcard instead. Same problem. Hmm, let us change the camera then so I switched to another Logitech camera (a USB1.1 camera). The problem remains. Ahh, it must be a Logitech driver problem, and I install a Philips camera instead. No change...... By know I pulling my hair I don't what else to try.
I then notice that although I have removed the Philips Aurilium physically from the system, Windows still thinks it is available. I go into the device manger and uninstall the Aurilium Sound Agent 2 device (this is a audio mixer device) and THEN it all starts working again. Finally!!!
The conclusion is to avoid the Philips Aurilium product if you need a audio device for emeetings and online conferencing.