In a bowl, combine the cake mix, oats and pumpkin pie spice. In another bowl, beat the egg, pumpkin and oil; stir into dry ingredients just until moistened.
Drop by 2 tablespoonfuls onto baking sheets coated with nonstick cooking spray; flatten with the back of a spoon. Bake at 350 degrees F for 18-20 minutes or until edges are golden brown. Remove to wire racks to cool.
In a bowl, combine confectioners' sugar, and enough orange juice to achieve desired spreading consistency. Frost cooled cookies.