The log looked like there may be a class conflict, possibly related to the wrong version of Deployment Manager being imported (which is why I was asking). Unfortunately, I do not know if Pega Rripples is included in the newer releases.
For 7.3+ customers, Pega released https://community.pega.com/marketplace/applications/deployment-manager. This offering is different from 7.1 and 7.2 versions, and is based on our market leading case management technology. This will be the one that we will support and enhance going forward in future. Unfortunately, we don't have Rripples feature in this yet, but we have plans to bring Rripples and more in the future versions of this offering.