Can't install docker containers

 OpenWrt SNAPSHOT, r22248-bf055fcdca
=== WARNING! =====================================
There is no root password defined on this device!
Use the "passwd" command to set up a new password
in order to prevent unauthorized SSH logins.
root@OpenWrt:~# /etc/docker-web
Unable to find image 'portainer/portainer:latest' locally
latest: Pulling from portainer/portainer
772227786281: Pull complete
96fd13befc87: Extracting [==================================================>]      92B/92B
a38f639c9d7e: Download complete
40d27ec7417c: Download complete
docker: failed to register layer: operation not supported.
See 'docker run --help'.

Linksys WRT1900 ACS