Hi I have the following snippet:

 var course = new Backend.DomainModel.UmbracoObjects.Course();
            course.CourseStart = DateTime.Parse(courseStart.Text);
            course.CourseEnd = DateTime.Parse(courseEnd.Text);
            course.Recurrence = repeatDropdown.SelectedValue;
            course.CourseValuePerHour = int.Parse(courseValueTextbox.Text);
            course.MaxCapacity = int.Parse(capacityTextbox.Text);
            course.Location = location.Text;
            course.CourseColor = "#" + courseColorTextbox.Text;

            using (var ctx = new Backend.DomainModel.UmbracoObjects.WilshireUmbracoContextDataContext())
            {
                var coursesNode = (from c in ctx.Coursess select c).Single();
                coursesNode.CoursesChildren.InsertOnSubmit(course);

            }

When I insert into the parrentnode I get the following: 

The NodeAssociationTree does not support Inserting items

So is it not possible to write nodes with lin2umbraco?