The only application capable of opening PRZ files is Lotus Freelance Mobile Screen Show Player. Unfortunately, I couldn't find a download for this application. I believe it's probably because it has been released a very long time ago and due to unknown reasons wasn't updated anymore.
There was a forum post on Lotus website with a link indicating a download URL, but that link leads to a general page on the Lotus website. Also, PRZ format is proprietary and unless you get a copy of Lotus Freelance Mobile Screen Show Player, then the possibility to open those files falls to 0.