It has been a while but what I did was the following.
I had a container which ran dremio, stopped that one.
Created a new container which shared the storage volumes and ran the restore command. Then the restores succeeds and you can startup the main dremio container again.
Yeah, I had the same issue and was stuck for a while.
I didn’t think anyone would reply 
Ah, okay — so the second container wasn’t running Dremio?
And the shared volume — does it contain all of the data, or just a certain folder?
My docker compose looked a little bit like this:
version: ‘3.3’
services:
dremio:
image: ....image....
container_name: dremio
hostname: dremiomaster
ports:
- '31010:31010'
- '32010:32010'
volumes:
- 'dremio-data:/opt/dremio/data'
restart: always
dremio-admin:
image: ....image....
container_name: dremio-admin
entrypoint: bash
volumes:
- 'dremio-data:/opt/dremio/data'
thks its worked for me