The previous generation of the web ui (Prime) has been deprecated since NSO version 4.5. In NSO release 5.1 it will be removed completely. Any example or application that is integrated with Prime will no longer work with this release and needs to be modified to work as stand alone ui application. Once the application is decoupled from Prime, it can be used in conjunction with the other tools and be included as an item in the Application hub.
For more information on how to deploy your own application and use it together with the other tools, take a look at this simple example on the NSO-developer GitHub.