I took a look at the walkthrough and it says this (pay particular attention to the last sentence):
Break open nuts:
Beg for food. She gives a rock to break open nuts.
Click to raise the arm.
Once the arm is just above Jep's bent head click again.
Wait for the green circle to around the nut and then click to break it cleanly.
10 nuts (seeds) are needed to finish the puzzle.
Easy mode is available by clicking on the cartoon at bottom right.
Have you tried doing this in easy mode?