I don't know...
You could try a using a live-cd while changing the order of the controller connections to the two SATA DVD drives and the HDD. Try the first three with the HDD as the third, mimicking Master-Slave, Master on a PATA controller.
The motherboard manual tells me that this board has RAID settings in the BIOS and an Auto-Configuration Option for the I/O controller. I would check the RAID settings for AHCI, not RAID, and choose manual configuration for I/O.
Upgrading to the latest BIOS might also be a very good idea.
As the manual states:
You can override the auto-configuration options by
specifying manual configuration in the BIOS Setup program.
It does seems that the DVD disks are found by linux as devices, but then linux becomes confused. The I/O problems shown might be caused by the controller settings.
Also, try the command "lsmod" to see what kernel modules are loaded for the drives.