I used the file you gave me earlier to flash back to stock: SPH-D700-EC05-8gb-REL.tar
The root/unroot I used before and now are:
one.click.root.exploitv2.5.5 to root
one.click.stock.flasher.&.root.uninstaller-di18 to unroot
I hadn't tried that earlier DRockstar file (didn't even see it, to be honest).
Why would one click fail?
From the log you posted it is not gaining superuser access first. I though all of those needed an "SU" in the first line. I am not an ADB expert though. It can't hurt anything to add it to the first line of the bat file.