Fatal error: Uncaught exception 'PDOException'...

Zdravím. Při zprovozňování webu mám tuto chybu:
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000] [2000] 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' in ...
Jak ji mám odstranit? Předem díky.
Už to je O.K.