This post will be spoiler free. :)
Thanks to everyone who helped with the puzzle last night. I did some looking around the web afterwards, and we basically had solved it. The step that kept killing me is apparently really buggy, and there were a couple of suggestions as to what to do to make it work right. (One method that apparently worked was a smuggler going into cover at the right time, so Celinda may do better at that than Conway.)
However, we wouldn't have quite been able to finish the puzzle, we need a couple more characters with the item that I linked in Op chat. If you want to know more about the item, let me know, I'll be happy to give you as much or as little of a clue as you want.
The end result is indeed a datacron, which is better than any other 2 datacrons for any class. Some sites say you can get it at level 46+, some say 50.
I find these puzzles more fun to find and solve in game than to go to any of the many web sites, so many thanks to folks for indulging me in some wipes. :)
I did the first part of the puzzle on Ahnesstee at level 19, up until the step that tells you "you must have more experience", so you don't have to wait till 50 to play around with this one.