I'm getting a cryptic error when trying to update the configuration of a single-container Docker application. Anybody have an idea of what might cause this, or how to go about debugging it?

```
ERROR [3009]  : Command execution failed:
   [CMD-ConfigDeploy/ConfigDeployStage0/ConfigDeployPreHook/00run.sh] 
   command failed with error code 1:
   /opt/elasticbeanstalk/hooks/configdeploy/pre/00run.sh
   docker: "tag" requires 2 arguments. See 'docker tag --help'.
   (ElasticBeanstalk::ActivityFatalError)

```