Soften or melt the butter. Mix in the eggs and peanut butter. Mix in 1/2 of the cake mix. Beat until blended well. Add the water somewhere in there. Mix in the rest of the cake mix and the chips. Beat until blended again. Pour into a greased 1" x 9" x 12" pan. Cook at 350 Degrees Fahrenheit until brown on top (about 17 minutes).