Leap Motion error messages

Hi everybody! I am pretty new in using Unity. I want to develop a simple video game for hand/finger rehabilitation in which the player has to grasp the fruits on the table using a pick and place gesture and put them on a plate. I have set up the Leap Motion: in the Hierarchy I insert the 'Leap Hand Controller' and the Interaction Manager. In order to interact with the fruits, I insert in these game objects the rigid boy component and the Interaction Behavior script. When pressing play no error messages appears. Then, I have exported the scenes: after having imported them in a new project, I press play, and error messages appear. As shown in the attached file, the errors are of two types. The first one is: 'NotFoundException:LeapC. The second one is: 'NullReferenceException: Object reference not set to an instance of an object'. Can someone explain to me why does it happen so and how to fix these problems? Thanks a lot.