Click button(dropdown button) next to the Add button in the Column Collection Editor to choose type of column. Click on Add button to add default type of the column.
I see that in your TreeListView Demo, you have dropped \"descriptionColumn\" component of type HierarchyColumn on the component tray. How did you do this? - I don't have (and cannot add) HierarchyColumn to the VS 2005 Toolbox.
See my previous answer, and screenshot below. You can add HierarchyColumn in Column Collection Editor by choose HierarchColumn from menu