The same thing happened to me when I did a new install of version 2 a little while back. I do remember it was a mistake on my side and I am trying to recollect what exactly it was I did. What comes to mind is that I used a version 1.7 db_settings.php file I already had all my MySql connection details in, then I realised that version 2 has additional tables which are not in the db_settings.php file of version 1.7.