It seems something went wrong when you installed WP.
- Download a fresh copy of WP to your desktop
- Use FTP to access your site
e.g. http://filezilla-project.org/download.php
Your webhost will probably have given you the ftp-access data - FTP:download the 'wp-config.php' file from your site
- FTP:UPLOAD the fresh WP-files; OVERWRITING the existing files
- FTP:Re-Upload the 'wp-config.php' to your site
- Browser: Check the result
Alternatively:
Instead of ftp use the webaccess dashboard functions provided by the webhost.
This usually is not as versatile and more cumbersome.