Can't create table 'db.#sql-388d_efa' (errno: 150)

Jeg må ikke tilføje FOREIGN KEY `studioID`, får fejlen:
Can't create table 'db.#sql-388d_efa' (errno: 150)

Håber nogen kan forklare den for mig, for kan ikke rigtig finde en løsning på Google



CREATE TABLE `<database name>`.`<table_name>` (
    `movieID` int(10) NOT NULL AUTO_INCREMENT,
    `title` varchar(100) CHARACTER SET latin1 NOT NULL,
    `imdb` char(9) CHARACTER SET latin1 NOT NULL,
    `released` int(4) DEFAULT NULL,
    `runtime` int(4) DEFAULT NULL,
    `website` varchar(50) CHARACTER SET latin1 DEFAULT NULL,
    `studioID` int(10) DEFAULT NULL,
    `added` timestamp NOT NULL ON UPDATE CURRENT_TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    `modified` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
    PRIMARY KEY (`movieID`),
    CONSTRAINT `movies_studioID` FOREIGN KEY (`studioID`) REFERENCES `<database name>`.`Studios` (`studioID`)  ON UPDATE RESTRICT ON DELETE RESTRICT,
    UNIQUE `imdb`(imdb),
    INDEX `movies_studioID`(studioID)
);

CREATE TRIGGER `on_modify` BEFORE UPDATE ON `<table_name>` FOR EACH ROW BEGIN
    SET new.modified = NOW();
END;