Can't format disk in Disk Utility while installing Leopard

Something happened while installing XP through bootcamp and now my partitions are gone and there's no operating systems on my drive. Now, when I boot from the leopard disc, and I go through Disk Utility, it does not let me partition or erase the drive. All options are greyed out. Is there something wrong with my new harddrive or did I just screw everything up?