Why getting: argument for routine is not a variable in MySQL routine?!


I am trying to get an INOUT parameter from MySQl using PHP and PDO but getting:

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1414 OUT or INOUT argument 2 for routine xoompage.sp_send_password_reset is not a variable or NEW pseudo-variable in BEFORE trigger' in C:\\xampp\\htdocs\\xoompage\\password_reset.php:17 Stack trace: #0 C:\\xampp\\htdocs\\xoompage\\password_reset.php(17): PDOStatement->execute() #1 {main} thrown in C:\\xampp\\htdocs\\xoompage\\password_reset.php on line 17

here is MySQL sp:

CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_send_password_reset`(IN param_member_guid varchar(255), INOUT param_password_reset_guid varchar(255))
	DECLARE param_password_reset_guid varchar(255);
	SET param_password_reset_guid = UUID();

	UPDATE members SET password_reset_guid = param_password_reset_guid, password_reset_date = DATE(NOW()) WHERE member_guid = param_member_guid;


and this is the PHP:

$mysql_query = $mysql_connection->prepare("CALL sp_send_password_reset(:param_member_guid, :param_password_reset_guid)");
$mysql_query->bindParam(':param_member_guid', $_SESSION["member_guid"], PDO::PARAM_STR);
$mysql_query->bindParam(':param_password_reset_guid', $password_reset_guid, PDO::PARAM_STR|PDO::PARAM_INPUT_OUTPUT, 4000);


Have a search around for Mysql Error 1414 - it seems (though I am not familiar enough with mysql to properly understand what’s going on) that this is a bug in some versions of Mysql.