[darwinbuild] Minimum Darwin Version

HI, What is the minimum version of Darwin/OpenDarwin needed to use these build scripts? I have been trying with OS X 10.2, OS X 10.3 and OpenDarwin x86 7.2. The most success has been with OS X 10.3. The problems that I have are with the darwinxref loadIndex. It spits out the usage a couple of times whenever I try to use it. Michael