Four times yesterday I tried to install the latest package and failed, my install method was to download the ISO and transfer it to a bootable USB stick (I used several methods, DISKPART, Rufus, DD all produced the same result.)
Then I found this thread: [SOLVED] Fresh install, "CRITICAL SYSTEM ERROR"
- which describes my symptoms exactly and also provided me with the method to use (burn ISO to disc and install - which worked without issue).
The install from USB route did mention something about not being able to find a kickstart file but also said I could just cancel the error to containue and me being a newbie to installing FreePBX did not realise the importance of this file.
Installing from DVD gave a very different install process and did fully install successfully.
I just thought I would highlight this.
The error that was received just in case someone tries to google it in future:
"** CRITICAL SYSTEM ERROR **
Unable to generate MOTD.
The /usr/sbin/fwconsole file is not accessible
You are likely to experience significant system issues."