The items returned by list_enrollments_sections no include the user_profile

[eriko]

 c_section_enrollment = @client.list_enrollments_sections(c_section.id, {type: 'StudentEnrollment', state: 'active'})
                    c_section_enrollment.each do |c_enrollment|
c_enrollement.user 

That last line is no longer valid call.
Instead you have to call c_user = @client.get_user_profile(c_enrollment.user_id) to get access to the user. This is a change from 0.6.11