When configuring Drupal 6.6 on a Windows XP/Apache/MySQL box, I ran into an issue whereby I would enter the database information on the Database Configuration screen, press the advance button, but be constantly redirected back to the Database Configuration screen.

The Drupal community indicates this is a problem with permissions - Drupal needs to be able to write to your site’s settings.php file.  All permissions appeared to be correct in my setup but I was still unable to continue.

The solution was to edit the settings.php file, putting in my database information manually.  Just look for this line:

$db_url = 'mysql://username:password@localhost/databasename';

And change the username, _password _and _databasename _parts.

Then return to the Database Configuration screen, enter the information again and continue.  The correct database information will be read from the settings file and the configuration will continue to the next step.

Happy hunting!