I miss the release notes for 3.1.2 in the release.notes.html file.
The names of the jpdl directories in feature and plugins are incorrect.
The name of the jpdl directory in feature is named as org.jbpm.gd.jpdl.feature_3.1.1 and in plugins is named as org.jbpm.gd.jpdl_3.2.0.alpha1.
This is obviously wrong. Let me correct this.
Thanks for reporting.
It should be fixed now. Sorry for the inconvenience.
Let us know if there are still problems.