Cannot Redeclare Class WPDB

Just went to a site of mine earlier today, and it was completely a white screen. It runs on Wordpress. I also went to try and login to the login url, and it was completely white as well. So, I went ahead and tried upgrading to the latest version of Wordpress, which just came o开发者_运维知识库ut today (3.0.4.), and I'm getting this error message when I try to login.

Fatal error: Cannot redeclare class wpdb in /home/username/domain.tld/blog/wp-includes/wp-db.php on line 53

Does anyone know how to fix this?

Hi Spencer B.:

Not sure why this is happening but have you tried wiping all files except for the files in /wp-content/ and the login credentials in /wp-config.php and replace with all new files from WordPress 3.0.4 using FTP? If you do this chances are it will detect any needed changes in your database and upgrade itself.

If you still get a white screen you might need to add a second theme, activate it and then reactivate the theme you want to use.

Hope this helps.

-Mike