Checking if your kit is complete... Looks good Writing Makefile for System2 Microsoft (R) Program Maintenance Utility Version 7.10.3077 Copyright (C) Microsoft Corporation. All rights reserved. cp io_test.pl blib\lib\io_test.pl cp System2.pm blib\lib\System2.pm AutoSplitting blib\lib\System2.pm (blib\lib\auto\System2) Microsoft (R) Program Maintenance Utility Version 7.10.3077 Copyright (C) Microsoft Corporation. All rights reserved. C:\cpanrun\build\5-10-0\bin\perl.exe "-Iblib\lib" "-Iblib\arch" test.pl 1..4 ok 1 Your vendor has not defined Fcntl macro F_GETFL, used at blib\lib/System2.pm line 79. NMAKE : fatal error U1077: 'C:\cpanrun\build\5-10-0\bin\perl.exe' : return code '0xff' Stop.