The statement in the system requirements to which you are referring, "QlikView Publisher is an additional licensed module of QlikView Server," means that in order to utilize it's functionality, it must be installed and licensed onto an exiting and functional QlikView Server. You (or whomever does your software purchasing) should know if you have a Publisher license. If you don't know suggest that you reach out to your Qlik account manager. The repository database is core set of files which Publisher uses to function. Natively, this set of files are XML files. Additionally, the repository database can be configure to use a SQL database instead of the XML files.
Hope this helps