i have ideneb 1.4 on a dvd and i cant boot

every time i try to install i get the "still waiting for root device" error and i cant find how to fix it

amd athlon 64 x2 3800+ 2.4ghz
ati radeon x1650 pro 512 mb pcie 0x71c1
windows drive: internal 250 (sata i think)
wanted mac drive: lacie 1tb external hdd