1. In a saucepan over medium heat, combine the cranberries, white sugar, and water. Cook, stirring occasionally until all of the cranberries have popped, and the mixture is thick, about 15 minutes. Remove from heat, and set aside to cool.
2. Preheat the oven to 350 degrees F (175 degrees C). In a large bowl, mix together the cake mix, melted butter, and eggs. Stir in the oats, brown sugar, ginger and cinnamon. Set aside about 1 1/2 cups of the mixture, and spread the rest into the bottom of a 9x13 inch baking dish. Pack down to form a solid crust, getting it as even as possible. Spread the cooled cranberry mixture over the crust. Pinch off pieces of the remaining mixture and place evenly over the cranberry layer.
3. Bake for 35 to 40 minutes in the preheated oven, until the top is lightly browned. Cool in the pan for about 40 minutes before slicing into bars.