Same problem here with a Creative Webcam 5. The last driver from Saillard's web solves de problem too. I attach the output from "camstream" because it says something about ioctl that I supose may be of help debuging the driver.
** Attachment added: "Output from camstream" http://librarian.launchpad.net/4703922/camstream-log.txt -- Regression: Webcams using pwc driver produce all-grey images https://launchpad.net/bugs/56090 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs