Fehlermeldung beim Installieren

Leider bekomme ich immer wieder eine Fehlermeldung wenn ich Drupal installieren möchte.
Was kann ich tun?
Warning: include_once(./sites/default/settings.php) [function.include-once]: failed to open stream: No such file or directory in /www/htdocs/xxxxxx/drupal1/includes/bootstrap.inc on line 243

Warning: include_once() [function.include]: Failed opening './sites/default/settings.php' for inclusion (include_path='.:/usr/share/php:..') in /www/htdocs/xxxxxx/drupal1/includes/bootstrap.inc on line 243

Warning: Cannot modify header information - headers already sent by (output started at /www/htdocs/w008b68e/drupal1/includes/bootstrap.inc:243) in /www/htdocs/xxxxxxx/drupal1/includes/common.inc on line 141
Unsupported database type

The database type is unsupported. Please use either mysql for MySQL 3.x & 4.0.x databases, mysqli for MySQL 4.1.x+ databases, or pgsql for PostgreSQL databases. The database information is in your settings.php file.

For more help, see the Installation and upgrading handbook. If you are unsure what these terms mean you should probably contact your hosting provider.

Ich habe PHP 5 und mysql 4.1

Vielen Dank für die Hilfe im Vorraus