Same problem on my end on Gateway p7905u FX. When I try PCIRootUID=1 -x, I simply get a blank screen (nothing displaying at all). When I first tried this, I got a loading bar of some kind, followed by the blank screen.
In my BIOS, there is no option available to set HPETs to 64-bit or any HPET options at all
In my case, I just installed default niresh to test it. My machine will boot fine using the USB bootloader, but after about 2 minutes I get the HPET error.
In addition, I am unable to boot to safe mode using the -s flag. I am able to, of course, run Terminal from the installer, so I'll try removing the power management kext from that.
Any assistance would be appreciated.