Looks like a couple of issues.
- “7za is not recognized” looks like the script was not able to download the free 7zip.exe to decompress the files.
- You maybe running the script in an unsupported version of UE4 (“Kernel version is unknown”
You can still try to install it, but I wouldn’t recommend it.
4.27 is unsupported on my script. Try manually installing. I haven’t got time to actually look into it.