Often the 7B error has to do with the SATA mode set in the BIOS - at least on our systems. Sometimes switching to a different mode will allow a system to boot.
Make sure you have both MfeEpePc.sys and MfeEEAlg.sys and that the services are set up properly in the registry. I also suggest trying my Winbuilder script. I think it allows you to make a much more flexible boot CD and also I made the script so it's pretty much browse and click.
