Welcome to Geeklog Saturday, May 18 2013 @ 08:47 PM EDT
Starting with Geeklog 1.3.10, you can edit the IDs of your stories. Since story IDs are not guaranteed to be generic any longer, Geeklog will check that you don't use the same story ID for two different stories.
So when you edit a story and get "The ID you chose for this story is already in use.", you either
FAQ Manager » Common problems » The ID you chose for this story is already in use.