I think I know where the problem is. Open config.php and change username to 'root' ($username = "root";).
I didn't see this post.
I've made the change but I'm still getting errors.
with the HTACCESS file:
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, admin@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
without the HTACCESS file:
Errore interpretazione XML: nessun elemento trovato
Linea numero 1, colonna 1:
Error interpretation XML: no elements found
Line number 1, column 1: