Opencore ocb loadimage failed - unsupported

CPU - I7 4770

GPU - GTX TITAN 6gb 2013

RAM - 16gb ddr3 1600 mhz

SSD - Western Digital Green 120GB

Motherboard - MSI H81I Mini ITX

Audio Codec - not sure, nvidia audio maybe

Ethernet Card is realtek i think

Guide followed - https://dortania.github.io/OpenCore-Install-Guide/ for high sierra, and i used this video https://www.youtube.com/watch?v=j-Cm30I_DEw&t=233s

I am attempting to install High Sierra. To get the High Sierra files i ran these 2 commands ( dont know why there are 2 but they are in the guide)

# High Sierra(10.13) python macrecovery.py -b Mac-7BA5B2D9E42DDD94 -m 00000000000J80300 download python macrecovery.py -b Mac-BE088AF8C5EB4FA2 -m 00000000000J80300 download 

And then dragged the files BaseSystem.chunklist and BaseSystem.DMG over to the com.apple.recovery.boot on my bootable USB.

My issue is that after high sierra has been installed to the SSD, i am returned to the Open core menu as expected. I then select macOS installer as per the video above, to finish the install. After about 10 seconds i get the message "Opencore ocb loadimage failed - unsupported", and nothing else and then i am returned to the opencore menu.

If i could get any help with this i would greately appreciate it. If you require any more information / files, let me know.