Invalid default value (3 replies)

When I execute this statement:

CREATE TABLE MG_FOLDER (
UUID CHAR(24) NOT NULL,
NAME VARCHAR(100),
OWNER VARCHAR(32),
CREATED TIMESTAMP,
MODIFIED TIMESTAMP,
ARCH BOOLEAN,
FOLDER_UUID CHAR(24),
SERIAL INTEGER,
CONSTRAINT FOLDER_PK PRIMARY KEY(UUID)
) ENGINE = InnoDB

I get this error:

Invalid default value for 'MODIFIED'

I don't think I specified any default value for MODIFIED, so what is causing the problem?