Call a method to add an array list input from another method in a different class to original class

I'm just starting out BlueJ and I can't figure out how to call a method that takes input from another method from a different class and adds the inputs to an array. By the way, this project is the "club" project from BlueJ.

Here is the error: http://ift.tt/1EcIkpg

The code with the error (the ".add" is highlighted to be the error):

(insert class, constructor, etc here)

    public void join(Membership member)
    {
        members.add(member);
    }

The method that I'm trying to call for the user inputs:

    public Membership(String name, int month, int year)
        throws IllegalArgumentException
    {
        if(month < 1 || month > 12)
        {
            throw new IllegalArgumentException(
                "Month " + month + " out of range. Must be in the range 1 ... 12");
        }
        this.name = name;
        this.month = month;
        this.year = year;
    }