I'm using Multi-configuration variables in the Dockerfile parameter box (Dockerfile.$ubuntu_release.$jdk in this example). They are used correctly in the error output but not in the actual docker build command, so the build fails:

{{Build Docker image from ./Dockerfile ...
$ docker build --tag 6e06fb3a96de83181451f73a093d1313f340d7f5 --file Dockerfile.$ubuntu_release.$jdk /home/core/jenkins/workspace/project/jdk/oraclejdk7/label/docker/ubuntu_release/lucid
The Dockerfile (Dockerfile.lucid.oraclejdk7) must be within the build context (/home/core/jenkins/workspace/project/jdk/oraclejdk7/label/docker/ubuntu_release/lucid)
FATAL: Failed to build docker image from project Dockerfile
java.lang.RuntimeException: Failed to build docker image from project Dockerfile
at com.cloudbees.jenkins.plugins.docker_build_env.Docker.buildImage(Docker.java:121)
at com.cloudbees.jenkins.plugins.docker_build_env.DockerfileImageSelector.prepareDockerImage(DockerfileImageSelector.java:41)
at com.cloudbees.jenkins.plugins.docker_build_env.DockerBuildWrapper.setUp(DockerBuildWrapper.java:152)
at hudson.model.Build$BuildExecution.doRun(Build.java:156)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:537)
at hudson.model.Run.execute(Run.java:1741)
at hudson.matrix.MatrixRun.run(MatrixRun.java:146)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:408)
Notifying upstream projects of job completion
Finished: FAILURE}}