I'm pretty sure that you go to the services desk (where you picked up and dropped off your FAL assignment). If I'm wrong, they'll definately be able to tell you where to go.
I believe that you can actually just email the librarian and they will send your marks to you....
There is a note on the law web pages from Fiona
Hello Everyone - Library Exercise results are now live on WebCt. To view your result, simply go to the FAL WebCT site and click on the Library Exercise results icon. Your result is shown as a mark out of 100. If you wish to see your graded Library Exercise, please email Debbie.Trew@anu.edu.au Regards Fiona