I am no longer working with Screenly, but back then I did get something working. I also tried to post a link to something useful and this forum decided the links were spam!
But good luck to anyone meeting all the same obstacles.
Sorry for the hours of frustration. The old install script that was throwing all those errors has since been retired. Installing is much simpler now: Anthias is available directly in the Raspberry Pi Imager, so you choose Anthias from the operating system list and write it to your SD card, no script needed. Marking this as solved. If you hit a snag with the current method, please open a fresh topic and we will be glad to help you through it.