Not a problem. Basically when we ask for the draft we want to see a piece that is probably mostly done. Maybe it hasn't been beta'd yet or it could still be missing scenes. This is most important for the people committed to writing 20K-if they've only written 5K we might be a bit concerned they'll be able to finish in time. Or maybe the author has decided to go from 5K to 20K and we can plan accordingly for posting purposes.
The draft is due about three months after sign-ups. We're hoping the bulk of the work is under your belt at that time and then you can polish it up before the final due date, roughly six weeks later.
Does that help? Feel free to follow up with more questions if necessary. :)