I'm Having the same issue!
Nobody (in parallels) seems to take this serious.
I have a Sony Laptop with a built in usb webcam. I made it work in Linux, but parallels doesn't want to add it at all So No sound, no Mic, no Camera!
Running Workstation build 2112, Ubuntu 6.10 host, Windoze XP guest.
I also get the damn error
Unable to open virtual bridge. Is it installed and started ?
Unable to connect USB device to virtual machine!
Error writing to sound device! Loopback device will be used!
Please, we need some help here!