Checking if your kit is complete... Looks good Writing Makefile for Math::Calculus::TaylorSeries s/MakeMaker.pm line 343. cp TaylorSeries.pm blib\lib\Math\Calculus\TaylorSeries.pm 8168.0 Copyright (C) Microsoft Corp 1988-1998. All rights reserved. D:\cpanrun\build\5-6-1\bin\perl.exe -Iblib\arch -Iblib\lib -Id:\cpanrun\build\5-6-1\lib -Id:\cpanrun\build\5-6-1\lib test.pl 1..6Can't locate object method "differentiate" via package "Math::Calculus::Expression" (perhaps you forgot to load "Math::Calculus::Expression"?) at blib\lib/Math/Calculus/TaylorSeries.pm line 149. NMAKE : fatal error U1077: 'D:\cpanrun\build\5-6-1\bin\perl.exe' : return code '0xff' Stop.