Why does Advanced Release Burndown report not showing optimistic, pessimistic and best guess lines?

It could be that none of the iterations selected for the report are the "current" iteration (the report considers the current iteration to be the iteration that is marked as current in the selected timeline - it doesn't go by the dates).  That would cause the optimistic, pessimistic and best guess lines not to be displayed on the chart (because those lines are projections from the current iteration to the planned release date).

 However, the RTC 3.0.1.x has a known defect where Advanced Release Burndown does not work correctly when release level iteration is not direct descendent of the timeline (214045). This defect has been fixed in 4.0.1