New White MacBook’s don’t see Netinstall Images

I have a Netboot server which I use to do Net-installs on all my Mac's at the office. I'm running 10.5.7 and I have updated my Admin Tools to 10.5.7. For some reason the new white MacBook's can't see or boot from my Net-install images. All my other Mac's are fine. I even tried created a new image using a new 10.5.6 System Disk. No dice. Any reason why the new MacBook's can't use NetBoot/Netinstall. I would hate to have to return these items. Aaron W.