Firewall may be a problem, have had mine not auto detect a request to allow a program through a few times now.
Does not sound good about the sql giving a problem, resolve that first.
the cause is probably the missing screen from the wiki where you have to choose that youre account is actually an admin in SQL .. see my comments on https://forum.team-mediaportal.com/website-forum-wiki-feedback-58/install-sql-server-wiki-missing-screenshot-37219/
Netherlands