After having some issues I totally found out I had my username instead of the userid in the config.php file.

Please CHECK your config.php file for obvious errors. Make sure it is version 3.0.3 if you run 3.0.3 and not an older version. And make sure you have used userid instead of username for settings.

For which settings?

The database should be username as there isn't a concept of userid there... and I think all of the config versions for vb3 have always used userid's in the arrays (such as the undeletable users array).

He probably means for the superadmin and such