CMake error trying to setup openCV, MinGW compiler

I've been trying to build openCV using CMake, but keep running into errors. I think I have MinGW setup properly.

I'm running the following command in C:\opencv\build\x86\mingw:

cmake -G "MinGW Makefiles" -D CMAKE_CXX_COMPILER=mingw32-g++.exe -D CMAKE-MAKE_PROGRAM=mingw32-make.exe ../../../sources

This gives the following error:

-- The CXX compiler identification is GNU 4.8.1 -- The C compiler identification is GNU 4.8.1 -- Check for working CXX compiler: C:/MinGW/bin/mingw32-g++.exe CMake Error: Generator: execution of make failed. Make command was: "mingw32-make.exe" "cmTryCompileExec1510977625/fast" -- Check for working CXX compiler: C:/MinGW/bin/mingw32-g++.exe -- broken CMake Error at C:/Program Files (x86)/CMake/share/cmake-3.2/Modules/CMakeTestCXXCompiler.cmake:54 (message): The C++ compiler "C:/MinGW/bin/mingw32-g++.exe" is not able to compile a simple test program.

It fails with the following output:

Change Dir: C:/opencv/build/x86/mingw/CMakeFiles/CMakeTmp

Run Build Command: "mingw32-make.exe" "cmTryCompileExec1510977625/fast"

The system cannot find the file specified

Generator: execution of make failed.

I was following the instructions found in berak's response to this question: Not sure how to build OpenCV for MinGW

Please provide some suggestions!

Thanks in advance.