Database help

I'm extremely new to this (n00b!) but I am having some troubles creating a table and I suspect the foreign key is the culprit.

Here's what I have done so far:

Create database test;
Use test;
Create Table students (sid char(20), name char(20), login char(20), age integer, gpa real);
Insert into students (sid,name,login,age,gpa) values (1, ‘Wayne’, ‘bwayne@123.com’,25, 3.95);
Insert into students (sid,name,login,age,gpa) values (1, ‘Kent’, ‘ckent@123.com’,27, 3.91);
Select * from students;
Update students s set s.age = s.age +1, s.gpa = s.gpa -1 where s.sid = 1;
Select * from students;
Alter table students add constraint unique (name,age);
Alter table students add constraint studentskey primary key (sid);

When I attempt to add the following I get 'Error 1005 (HY000): Can't create table 'testing.enrolled' (errno: 150)

create table enrolled (studid char(20),cid char(20),grade char(10),primary key (studid, cid),foreign key (studid) references students);


Any help would be greatly appreciated! As I said, I'm very new to this and am probably doing something easy, incorrectly.

OMG. I'm an idiot.