Automatically Add to iTunes folder not working

Ever since upgrading to iTunes 9 I have been using the "Automatically Add to iTunes" folder to drop new movies (.m4v) and have them added to iTunes. Just noticed that it has stopped working. The files just sit there and don't get added. I realize I can just drag them to itunes myself, but I'm curious why the folder stopped working and if anyone knows a way to get it working again?