CPM failed to get the hash for HEAD - visual-studio-2012

Question

I'm trying to use CMake for the following CMakeLists.txt:
cmake_minimum_required(VERSION 2.8.0 FATAL_ERROR)
#-----------------------------------------------------------------------
# CPM configuration
#-----------------------------------------------------------------------
set(CPM_MODULE_NAME "arc_ball")
set(CPM_LIB_TARGET_NAME ${CPM_MODULE_NAME})
if ((DEFINED CPM_DIR) AND (DEFINED CPM_UNIQUE_ID) AND (DEFINED CPM_TARGET_NAME))
set(CPM_LIB_TARGET_NAME ${CPM_TARGET_NAME})
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CPM_DIR})
include(CPM)
else()
set (CPM_DIR "${CMAKE_CURRENT_BINARY_DIR}/cpm-packages" CACHE TYPE STRING)
find_package(Git)
if(NOT GIT_FOUND)
message(FATAL_ERROR "CPM requires Git.")
endif()
if (NOT EXISTS ${CPM_DIR}/CPM.cmake)
message(STATUS "Cloning repo (https://github.com/iauns/cpm)")
execute_process(
COMMAND "${GIT_EXECUTABLE}" clone git#github.com:iauns/cpm.git ${CPM_DIR}
RESULT_VARIABLE error_code
OUTPUT_QUIET ERROR_QUIET)
if(error_code)
message(FATAL_ERROR "CPM failed to get the hash for HEAD")
endif()
endif()
include(${CPM_DIR}/CPM.cmake)
endif()
#-----------------------------------------------------------------------
# CPM Modules
#-----------------------------------------------------------------------
# ++ MODULE: GLM
CPM_AddModule("GLM"
GIT_REPOSITORY "https://github.com/iauns/cpm-glm"
GIT_TAG "1.0.2"
USE_EXISTING_VER TRUE
EXPORT_MODULE TRUE # Use EXPORT_MODULE sparingly. We expose GLM's interface
) # through our own interface hence why we export it.
# This call will ensure all include directories and definitions are present
# in the target. These correspond to the modules that we added above.
CPM_InitModule(${CPM_MODULE_NAME})
#-----------------------------------------------------------------------
# Source
#-----------------------------------------------------------------------
# Globbing has some downsides, but the advantages outweigh the
# disadvantages.
file (GLOB Sources
"arc-ball/*.cpp"
"arc-ball/*.hpp"
)
#-----------------------------------------------------------------------
# Library setup
#-----------------------------------------------------------------------
# Build the library.
add_library(${CPM_LIB_TARGET_NAME} ${Sources})
if (NOT EMSCRIPTEN AND CPM_LIBRARIES)
target_link_libraries(${CPM_LIB_TARGET_NAME} ${CPM_LIBRARIES})
endif()
My system is windows 8.1 and I'm using Visual Studio 11 2012 as a generator. However when I try to configure, I get the following error:
CMake Error at
CMakeLists.txt:26 (message):
CPM failed to get the hash for HEAD
Meaning that it's happening on that line:COMMAND "${GIT_EXECUTABLE}" clone git#github.com:iauns/cpm.git ${CPM_DIR}
Would anyone know why?
Thanks in advance for the help.