Hi,
mojoPortal only depends on SQL Server, but SQL Server may depend on those objects, or the Platform Installer might think it does. I would just let it install those if it wants to. It should be installed on the same machine as the database but the database does not have to be installed on the same machine as the web app. But I'm not sure if Platform Installer can handle it if the db is on a different machine or not.
Hope that helps,
Joe