The files linked in there are out of date.
I would download the 4.4.4 factory image which is here
, install the Google USB driver
, then install ADB/Fastboot
and then run the batch file in the factory image with your phone in the bootloader to roll back to stock. Then lock your bootloader with fastboot oem lock
PHONES: iPhone 3GS (Retired, Jailbroken, iDroid, overclocked to 800MHz) -> Motorola Atrix 4G (Shattered, CM10, Faux kernel @ 1.45 ghz overclocked) -> Google/LG Nexus 4 16GB (Backup Phone, L Preview) -> Google/LG Nexus 5 32GB (Primary Phone, L Preview)
TABLETS: Sony Tablet S (Retired, rooted 4.0.3), Surface Pro 2 128GB (Current, W8.1)