MySQL error!

Error establishing a database connection!

(mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication. Please use an administration tool to reset your password with the command SET PASSWORD = PASSWORD('your_existing_password'). This will store a new, and more secure, hash value in mysql.user. If this user is used in other scripts executed by PHP 5.2 or earlier you might need to remove the old-passwords flag from your my.cnf file)

1. Are you sure you have typed the correct user/password?
2. Are you sure that you have typed the correct hostname?
3. Are you sure that the database server is running?