Comment 2 for bug 432155

I have a similar problem with a non-ppc box (freeze during boot that requires a hard reset); mine is a Phenom II X4 945 w/ Radeon 4850HD. I also get the udev errors but am not sure that the two are related, since lots more happens afterwards. Anyway, here they are.
Sep 18 16:42:09 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:3
Sep 18 16:42:09 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:4
Sep 18 16:42:09 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:5
Sep 18 16:42:09 ubuntu udevd[2070]: unknown key 'SYMLINK{unique}' in /lib/udev/rules.d/50-udev-default.rules:3
Sep 18 16:42:09 ubuntu udevd[2070]: unknown key 'SYMLINK{unique}' in /lib/udev/rules.d/50-udev-default.rules:4
Sep 18 16:42:09 ubuntu udevd[2070]: can not read '/etc/udev/rules.d/z60_hdparm.rules'
Sep 18 16:42:10 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:3
Sep 18 16:42:10 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:4
Sep 18 16:42:10 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:5
Sep 18 16:42:10 ubuntu udevd[2070]: unknown key 'SYMLINK{unique}' in /lib/udev/rules.d/50-udev-default.rules:3
Sep 18 16:42:10 ubuntu udevd[2070]: unknown key 'SYMLINK{unique}' in /lib/udev/rules.d/50-udev-default.rules:4
Sep 18 16:42:10 ubuntu udevd[2070]: can not read '/etc/udev/rules.d/z60_hdparm.rules'
Sep 18 16:42:10 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:3
Sep 18 16:42:10 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:4
Sep 18 16:42:10 ubuntu udevd[2070]: NAME="%k" is superfluous and breaks kernel supplied names, please remove it from /lib/udev/rules.d/40-ppc.rules:5