I'm having the same problem. I've finished Ranear's Salvation. My char is 23k, but the skirmish shows locked. If it helps, I did get into the skirmish a few months ago through a random queue and it failed.
One major problem I see with the cryptic logic is that they assume everyone has empty char slots where they can make a healer. The ftp players only have 2 slots. If they already filled them with dps or tank, then they either have to spend rl money or they have to delete a char to make a healer. Probably not going to happen…
I have four more fragments, but never got the quest again. They are just sitting there so I guess we only get one box. Is there any reason to keep running Stardock quests?