Thanks a lot Dear Matt and Bruce, Finally i got my Perl script running using, BEGIN { $ENV{IFEFFIT_DIR} = 'C:\Program Files\Ifeffit\'; } at the begining of my program.... I have added the environment variable IFEFFIT_DIR, but it does not seem to make a difference. I have tried.......... "C:\Program Files\Ifeffit\wrappers\perl\build, and do perl Makefile.PL nmake install" after editing makefile.pl as per... "'LIBS' => [' -LC:\"Program Files"\Ifeffit ifeffit_10 ']," and also copied ifeffit.pm to C:\perl\site\lib... I have visual studio installed on my computer, however the nmake command does not seem to be working. SCREEN DISPLAY AFTER THE CHANGES: C:\Program Files\Ifeffit\wrappers\perl\build>perl makefile.pl Note (probably harmless): No library found for oldnames.lib Note (probably harmless): No library found for kernel32.lib Note (probably harmless): No library found for user32.lib Note (probably harmless): No library found for gdi32.lib Note (probably harmless): No library found for winspool.lib Note (probably harmless): No library found for comdlg32.lib Note (probably harmless): No library found for advapi32.lib Note (probably harmless): No library found for shell32.lib Note (probably harmless): No library found for ole32.lib Note (probably harmless): No library found for oleaut32.lib Note (probably harmless): No library found for netapi32.lib Note (probably harmless): No library found for uuid.lib Note (probably harmless): No library found for ws2_32.lib Note (probably harmless): No library found for mpr.lib Note (probably harmless): No library found for winmm.lib Note (probably harmless): No library found for version.lib Note (probably harmless): No library found for odbc32.lib Note (probably harmless): No library found for odbccp32.lib Note (probably harmless): No library found for msvcrt.lib Writing Makefile for Ifeffit C:\Program Files\Ifeffit\wrappers\perl\build>nmake 'nmake' is not recognized as an internal or external command, operable program or batch file. Regards, Satyender Goel