Disk location or size should not matter for installation as long as you have support for the SATA disk controller. Try a more recent 10.5.6 distro, I'm not even sure whats that iAtkos 1.0ir2...
You can see the full installation log in the menubar.
You cant boot a retail disk on a PC straight, you need a bootloader like boot132 or chameleon2, either on a CD or on a USB Drive.