WordPress 3.0 blog upgrade error solution (DB Cache Reloaded plugin)

Have you recently upgraded your blog to WordPress 3.0 and got an error and did not find solution. Most of this errors are caused by DB Cache Reloaded plugin if you have installed it.

The error will be something like this -

[03-Jun-2010 12:46:19] PHP Fatal error: Call to undefined method wpdb::get_blog_prefix() in /home/www/XXX/domain.com/webroot/wp-admin/includes/user.php on line 260

[03-Jun-2010 12:46:19] PHP Fatal error: Call to undefined method wpdb::get_blog_prefix() in /home/www/XXX/domain.com/webroot/wp-admin/includes/user.php on line 445

If you are using DB Cache Reloaded plugin and is in active mode then it will be using a custom WPDB file which will replace the original one. So deactivate the DB Cache Reloaded plugin and your problems will be solved. An updated version of DB Cache Reloaded plugin is awaited from the author so that this bug is solved.