phpBB : Critical Error

Could not connect to the database PHP Warning: mysql_connect(): OK packet 6 bytes shorter than expected in C:\Siti\siti_spe\propri\auto\contravvenzioni.it\forum\db\mysql4.php on line 48 PHP Warning: mysql_connect(): mysqlnd cannot connect to MySQL 4.1+ using old authentication in C:\Siti\siti_spe\propri\auto\contravvenzioni.it\forum\db\mysql4.php on line 48 PHP Warning: mysql_error() expects parameter 1 to be resource, boolean given in C:\Siti\siti_spe\propri\auto\contravvenzioni.it\forum\db\mysql4.php on line 330 PHP Warning: mysql_errno() expects parameter 1 to be resource, boolean given in C:\Siti\siti_spe\propri\auto\contravvenzioni.it\forum\db\mysql4.php on line 331