Is manually editing player files meant to be done? I tried to edit the file and entered everything in(completed=true, time elapsed, skills used, lemmings saved, score), but it didn't work. I copy-pasted it and changed the group and level numbers to the correct ones.
Edit: Looks like I didn't think to see if the level numbers started on 0 instead of 1.
It seems, though, that the next level is marked as completed, but it doesn't load the next level(the level just says completed and has all of the things I entered in it, it's just that the next level isn't accessible). I suggest that you do something that makes the program reload the player file on startup or something of the sort.