Okay. Why bother to tell me this again?
Perhaps you are unaware of how to copy and paste. First, you use the little 'Copy' button and mark out the area with the red border lines by dragging the mouse across the terrain. Then, you push the 'Paste' button and when you do, the red-marked area will show on your terrain. It is at that point when you use those two keys to rotate the placement of the red area. If you use those keys while still in the "Copy" mode nothing will happen. It is only when PLACING the copied area that you can rotate it.
Please, try again
Bill