This module requires the following C libraries: gmp-4.2.0 (or later) mpfr-2.3.0 (or later) Building without 64-bit 'long long' support If this is wrong, see the "64-bit support" section in the README Building without 'long double' support If this is wrong, see the "64-bit support" section in the README Checking if your kit is complete... Looks good Note (probably harmless): No library found for -lmpfr Note (probably harmless): No library found for -lgmp Writing Makefile for Math::MPFR Microsoft (R) Program Maintenance Utility Version 6.00.8168.0 Copyright (C) Microsoft Corp 1988-1998. All rights reserved. cp MPFR.pm blib\lib\Math\MPFR.pm C:\cpanrun\build\5-10-0\bin\perl.exe C:\cpanrun\build\5-10-0\lib\ExtUtils\xsubpp -typemap C:\cpanrun\build\5-10-0\lib\ExtUtils\typemap -typemap typemap MPFR.xs > MPFR.xsc && C:\cpanrun\build\5-10-0\bin\perl.exe -MExtUtils::Command -e mv MPFR.xsc MPFR.c cl -c -nologo -GF -W3 -MD -Zi -DNDEBUG -O1 -DWIN32 -D_CONSOLE -DNO_STRICT -DHAVE_DES_FCRYPT -DUSE_SITECUSTOMIZE -DPRIVLIB_LAST_IN_INC -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX -MD -Zi -DNDEBUG -O1 -DVERSION=\"2.02\" -DXS_VERSION=\"2.02\" "-IC:\cpanrun\build\5-10-0\lib\CORE" -DNEWPERL MPFR.c MPFR.c MPFR.xs(6) : fatal error C1083: Cannot open include file: 'gmp.h': No such file or directory NMAKE : fatal error U1077: 'cl' : return code '0x2' Stop.