Cannot access the Hardware Clock via any known method

So your hardware clock can't be accessed on Linux? Here's a quick fix for your problem!

modprobe rtc-cmos

Without rebooting, try and access the clock again with the hwclock command. If it works, then you can make this permanent using one of the following commands. Make sure you are root or use sudo when you do these commands. If you are not listed here, look up how to automatically load a module for your distribution.

Ubuntu

echo "rtc-cmos" >> /etc/modules

Gentoo

echo "modules=\"rtc-cmos\"" >> /etc/conf.d/modules

Fedora

echo "rtc-cmos" >> /etc/modprobe.conf

If you don't have the rtc-cmos module, make sure you enable it in your kernel config under Device Drivers -> Real Time Clock