I'm getting the same error after updating to 6.0.1.
Jul 1 18:48:16 spacecataz php: /usr/local/emhttp/plugins/dynamix.docker.manager/event/started;/usr/local/emhttp/plugins/dynamix.docker.manager/dockerupdate.php
Jul 1 18:48:16 spacecataz php: Starting Docker...
Jul 1 18:48:16 spacecataz logger: starting docker ...
Jul 1 18:48:30 spacecataz php: Updating templates... Updating info...
Jul 1 18:48:30 spacecataz php: Warning: stream_socket_client(): unable to connect to unix:///var/run/docker.sock (No such file or directory) in /usr/local/emhttp/plugins/dynamix.docker.manager/dockerClient.php on line 505
Jul 1 18:48:30 spacecataz php: Couldn't create socket: [2] No such file or directory
Jul 1 18:48:30 spacecataz php: Warning: Invalid argument supplied for foreach() in /usr/local/emhttp/plugins/dynamix.docker.manager/dockerClient.php on line 364
Jul 1 18:48:30 spacecataz php:
Jul 1 18:48:30 spacecataz php: Warning: file_put_contents(): Only 0 of 4 bytes written, possibly out of free disk space in /usr/local/emhttp/plugins/dynamix.docker.manager/dockerClient.php on line 365
Jul 1 18:48:30 spacecataz php: Done.
Jul 1 18:48:52 spacecataz emhttp: /usr/bin/tail -n 42 -f /var/log/syslog 2>&1
Edit: Looks like my thumb drive ran out of space. I guess 1GB will not cut it anymore. 16GB thumb drive worked great!