I used to work for Iomega Tech Support, I remember this happening if your MB has a seperate ATA 100 controller (Promise/ HighPoint or whatever) and if you connect it to this then this will cause this ...
I set up my file server last night with a software RAID-1 array, using a pair of 160GB Maxtor drives hooked up to a SIL-680 PCI controller. The array created correctly, and I formatted it and mounted ...