Looking at this page; http://www.boonex.com/forums/#forum/Dolphin-7-1-0.htm, and the stickies, it is hard to see a pattern. It is not by creation date or last reply date. So I am guessing it is by the date the topic was made a sticky. So if you have two forum topics, one created 389 days ago (ageing still stinks, use the post date, members know post date because that is what humans use; why make them use a calculator to get the bleeding post date?), and one created 234 days ago. If post date 234 days ago was made a sticky first, then post 234 sticky will appear before post date 389. That is just a guess, I don't know how it works.
If it is by date made a sticky, then one could create a hack to order them based on this field. Otherwise edit the database directly. If time, I could try to figure this out by examining the code.
Uh, is the boonex forum the same orca forum we are using, or should I be looking at a Dolphin site?