I followed to a T the instructions creating a minimal netinstall image and captured it using Composer, then used SIU to create the netboot image. I also enabled diskless netboot for the NBI. When I boot to it and launch Casper Imaging the selected configuration immediately fails when it tries to block copy the image with the NilObjectException error.
I verified this does not occur when running the same job booted to an external drive with Lion installed, so it apparently is rooted in the netboot image I made. I am not sure what the issue could be because as I said I followed the steps exactly as provided by the knowledge base. I have a vague sense it may be a read/write error but composer does not allow you to specify that IIRC.
Any ideas? I have a support ticket open but the thought is because it is the NBI I may be on my own.