Why does the system fail to boot and give the error "Could not find kernel image: /NULL"?

Question

FreeBSD

I can't run freebsd on a thin client , it
says:
Could not find kernel image: /NULL
before, just a dash was blinking. I'm booting
from a
Live cd
. I didn’t understand why NULL and what it means I
wrote it to a USB flash drive through universal-usb-installer,
I chose the Try Unlisted Linux ISO section
. freebsd there was no section listed