I am getting issues with a Joomla install (problem is available both in 1.5.13 and 1.5.15) that will not order articles inside a category or section blog layout.
I have attempted setting the type order around the layout by hand to all of the different sort options however it doesn't have effect.
Ordering around the top of the page works fine.
In the variety of recption menus item (i.e. whenever you click on the item title), look around the right hands side and click on "Parameters (Advanced)".
You need to set Category Order to "No, order by Primary Order only" and Primary Order to "Default" (or "Newest first" in the event that does not work).
You have to Enable Custom Ordering...