This means that are not using APM or ACPI, check wich you motherboard uses then make sure it is loaded as a module or compilied into the kernel.
try
for starters.
I'm not sure if the model is called apm as I have mine compilied into the kernel.
Also 'shutdown -r now' will reboot the system you should use 'shutdown -h now' to halt the system.
Regards
Shmonkey