Hmm, this shouldn't be happening, but try username "admin", password "admin".
Its curios - I have repeated this several times. But now the admin screen does appears - I don't know why - but I am happy. Thank you for your assistance
I am on a trial and error job because I try to work with nusphere and moodle. In this job I have now installed several times moodle newly. In the last 4 times I had the same error again! admin/admin does not work.