multi-db error, no websites

Warning: mysql_get_server_info(): supplied argument is not a valid MySQL-Link resource in /home/leonaaz/public_html/wp-content/db.php on line 669

Warning: Cannot modify header information - headers already sent by (output started at /home/leonaaz/public_html/wp-content/db.php:669) in /home/leonaaz/public_html/wp-includes/functions.php on line 3191
Error establishing a database connection

What is the cause for this error. When trying to get to the websites this error appears. When I remove db.php, the error goes away?

The databases all appear in myPHP and all the 20 sites continue to work if dp.php is removed.