So, to clarify...

Download 80 RAR files from RS. Unzip #1, that will jump to the next to the next to the next and create one 8gig ISO file. Burn the ISO with IMGBurn ("Write image file to disc") and you should have a working disc.

Tell your friend to burn the disc at the slowest possible speed. Some burners and machines have trouble burning dual layer discs at higher speeds. You might also want to disable things like virus scan, screen savers and any other system activity based programs that run on startup. They've caused burning problems on occasion too.