Enrolment

Okay, firstly, I appologise if this has already been covered elsewhere, but i've searched and can't find anything relevent to my situation.

I'll start by saying what I need:

• students should be able to be enrolled in one or more courses.
• only those courses in which the student is enrolled should appear in "My courses" when they log in.
• students should not be able to enrol themselves in a course.
• guests should have no access to anything.
• A student should not have access to a course in which they aren't enrolled

I think that I have the right setup for this, however, even though students are enrolled in a given course (which appears in their 'My courses' area), when they click on the course name to access the course, they are shown a screen that says "This course is not enrollable at the moment."

I have set the course not to be enrollable because students shouldn't be able to enrol themselves in it. however this message appears for uses who have been explicitly given the role of 'student' within that particular course.

Any help would be greatly appreciated.
Regards,
Ed