Add Deployment Unit throws RTE

Following the "Business Automation Community Release Checklist" for "Test native (DRL) decision services". Step "2.6.1. Creating a deployment unit in Business Central" after having created and installed a project with jbpm-server-distribution-7.34.0.Final-dist.zip I clicked "Add Deployment Unit" and then selected the project I'd previously built from the "New Deployment Unit" dialog. The attached RTE resulted.

After dismissing the error and clicking "Finish" I could start the new container successfully.