Error on running the Grayscale application

I am new to OpenCL so I have been working on some simple Opencl c++ programming. I have written a code on Gray scaling using OpenCL and OpenCV. It has been compiled properly, but on run it gives me the following error: -

Platform Found : ARM Platform
terminate called after throeing an instance of ‘cl::Error’
what() : clCreateKernel

I have been writing the code on Ubuntu, using vim editor.
My host code is : -

int main( int argc, char** argv )
cl_int error = 0 ;

//Load image using OpenCV

IplImage *src = cvLoadImage("/home/akash/Desktop/Bird.jpg",CV_LOAD_IMAGE_COLOR );

IplImage *result_image = cvCreateImage(cvGetSize(src), IPL_DEPTH_8U, 1);

const int width = src->width;
const int height =src->height;
unsigned char *vec_h;

// long count = width*height;

// std::vector<float> size(width*height,1);
vec_h = (unsigned char )malloc((widthheight)*sizeof(unsigned char));

std::vector&lt;cl::Platform&gt; plat;

	//Find OCL platform
	string value;
		std::cout&lt;&lt;"No platform found"&lt;&lt;std::endl;
		cout&lt;&lt;"Platform found : "&lt;&lt;value&lt;&lt;endl;

	//Find device

		std::cout&lt;&lt;"No device found"&lt;&lt;std::endl;

	 // Context Properties

	 cl_context_properties props[3] = {CL_CONTEXT_PLATFORM,(cl_context_properties)(plat[0]), 0};

	 //Create Context

	 cl::Context ctxt(dev,props,0,0,&error);

	 //Create CommandQueue

	 cl::CommandQueue cque(ctxt,dev[0],0,&error);

	 //Create Program

	 std::ifstream sourceFileName("/Grayscale/");
	 std::string sourceFile(std::istreambuf_iterator&lt;char&gt;(sourceFileName),(std::istreambuf_iterator&lt;char&gt;()));
	 cl::Program::Sources graysrce(1,std::make_pair(sourceFile.c_str(),sourceFile.length()+1));
	 cl::Program prog(ctxt,graysrce);


	 //Create Kernels

	 cl::Kernel kernel(prog,"Grayscale",&error);

	 //Memory Objects
	 cl::Buffer input, output;

	 input = cl::Buffer(ctxt,CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR,width*height,NULL,&error);

	 output =cl::Buffer(ctxt,CL_MEM_WRITE_ONLY,width*height,0,&error);

The error is at clCreateKernel so I have added code till that only.
Any ideas?? Thanks for the help!!