Either you have filled two colors as one by one or white as default (auto-filled)color filled while creating a new shape and then u filled brown color. Hence, two shapes are created in one object itself.
Simply you select a shape, hold down "shift" key and press "Down arrow" key. Then you can see the white filled shape. Now you select the white shape and delete it. After deleting, select the brown shape and bring to front. To do this press the "Up arrow" key while holding "shift" key.
(Making more shapes at single object is, the best option in AS. I haven't seen this option, in other any vector 2d animation Softwares)
Here is the file, which is the white line removed.
http://www.mediafire.com/download.php?fmynkmhqme5