I assume that you are trying to format them as part of the install.
Generally that is caused by the RAID controller options. Turn off RAID and/or set the option to emulate IDE until after install. You can then switch it back if you wish. It is doubtful that you will see a performance increase anyway. Barring not doing that you will have to load a driver from floppy at the first screen during installation. See if your motherboard manual mentions where and how to find the driver.