Checking if your kit is complete... Looks good Writing Makefile for Crypt::Rabbit Microsoft (R) Program Maintenance Utility Version 6.00.8168.0 Copyright (C) Microsoft Corp 1988-1998. All rights reserved. cp Rabbit.pm blib\lib\Crypt\Rabbit.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 Rabbit.xs > Rabbit.xsc && C:\cpanrun\build\5-10-0\bin\perl.exe -MExtUtils::Command -e mv Rabbit.xsc Rabbit.c cl -c -I. -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 -O3 -funroll-loops -fomit-frame-pointer -fschedule-insns2 -Os -fno-strength-reduce -Wall -pipe -DVERSION=\"1.0.0\" -DXS_VERSION=\"1.0.0\" "-IC:\cpanrun\build\5-10-0\lib\CORE" Rabbit.c Command line error D2021 : invalid numeric argument '/Wall' NMAKE : fatal error U1077: 'cl' : return code '0x2' Stop.