CMake problem for a Gphoto2

[shopenhowe]

For building the attached cpp file I receive CMAKE_MODULE_PATH error while running make command on Terminal.
It uses Gphoto2 and OpenCV to capture live images from a digital camera. This files is based on
http://docs.opencv.org/master/db/d56/tutorial_capture_graycode_pattern.html#gsc.tab=0
I believe the problem is caused by a wrong CMakeLists.txt file, however I do not know how to fix it.
Thanks for your guidance in advance.

======================================================================
grayp.cpp file
====================================
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/structured_light.hpp>
#include <iostream>
#include <stdio.h>
using namespace cv;
using namespace std;
int main( )
{

// Open camera, using libgphoto2
VideoCapture cap1( CAP_GPHOTO2 );

if( !cap1.isOpened() )
{
// check if cam1 opened
cout << "cam1 not opened!" << endl;}
else
cout <<"FFFFFFFFFFFFFFFF"<< endl;

// the camera will be deinitialized automatically in VideoCapture destructor
cout << "Closing program" << endl;
return 0;
}

===============================================================================
CMakeLists.txt
===========================================
cmake_minimum_required(VERSION 2.8)
project( grayp )
find_package( OpenCV REQUIRED )
add_executable( grayp grayp.cpp )
target_link_libraries( grayp ${OpenCV_LIBS} )
option(GPHOTO2 "test" ON)
find_package( GPHOTO2 REQUIRED )
include_directories(/usr/local/include/gphoto2)
include_directories(/home/pi/Downloads/libgphoto2-2.5.9/libgphoto2)
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/home/pi/code/prof/gray")