1) Extract the 'PES 2016 TheViper12 Version 1.0 Xbox 360.7z' 7zip files. There are 6 files that you need to download to extract successfully.
2) Inject the files with Horizon onto the USB. You do not need to inject them in any order or any folder (Horizon will do this for you). Random order worked for me.
3) Unzip 'PES 2016 TheViper12 Version 1.1 Xbox360' and inject. It will replace the existing 'Viper2' file of v1.
4) Insert USB in Xbox
5) Copy to HDD.
6) Run game