Oh gosh! This was intense. I'm a first time flash user, and, like EVERYONE pretty much, my missiles weren't working. At first they would just stay still... And they ended up staying still even after I finished the coding. I HONESTLY suggest making a missile in paint, or going to this page: http://www.kongregate.com/labs and clicking the link to download the scion toolbox, which has a neat little fire missile.
Once I did that, I just followed the steps to set it up, but like this: Insert>New Symbol (missile, missile missile, and check import, just like the shootorial) and then File>Import to Stage and then I clicked the picture I made in paint/the scion image.
and then it worked.
 "Shootorial #3"){kind=icon}
 "Sprout"){kind=icon}