sql cannot add foreign key constraint - mysql

Question

i am trying to create a table that uses a foreign key from another table an i keep getting the error:"1215 cannot add foreign key constraint "
i checked and it says the following:
"Cannot find an index in the referenced table where the
referenced columns appear as the first columns, or column types
in the table and the referenced table do not match for constraint.
Note that the internal storage type of ENUM and SET changed in
tables created with >= InnoDB-4.1.12, and such columns in old tables
cannot be referenced by such columns in new tables.
See http://dev.mysql.com/doc/refman/5.6/en/innodb-foreign-key-constraints.html
for correct foreign key definition."
below is my sql code:
show engine innodb status;
CREATE TABLE trainee (
traineeid bigint unsigned NOT NULL,
fname VARCHAR(20),
lname VARCHAR(20),
id INT(9),age INT,
PRIMARY KEY (traineeid));
CREATE TABLE trainer(
trainerid bigint unsigned NOT NULL,
fname VARCHAR(20),lname VARCHAR(20),
id INT(9),
PRIMARY KEY (trainerid));
CREATE TABLE club(
clubid bigint unsigned NOT NULL,
clubname VARCHAR(20),
PRIMARY KEY(clubid));
CREATE TABLE team(
teamid bigint unsigned NOT NULL,
teamname VARCHAR(20),
clubid bigint unsigned,
INDEX(clubid),
FOREIGN KEY (clubid) REFERENCES club (clubid)
ON DELETE SET NULL
ON UPDATE CASCADE,
PRIMARY KEY(teamid));
CREATE TABLE competition(
competitionid bigint unsigned NOT NULL,
competitiondate DATE,
competitionname VARCHAR(40),
PRIMARY KEY(competitionid));
CREATE TABLE trainertoteam(
trainerid bigint unsigned not null,
teamid bigint unsigned not null,
PRIMARY KEY(teamid,trainerid),
INDEX(trainerid),
FOREIGN KEY (trainerid) REFERENCES trainer (trainerid)
ON DELETE set null
ON UPDATE CASCADE,
INDEX(teamid),
FOREIGN KEY (teamid) REFERENCES team (teamid)
ON DELETE CASCADE
ON UPDATE CASCADE);
could you help me to find what is the error?
i know the error is when creating trainertoteam table