Updating GEMS using nmake

I am trying to update the win32-api (standard) gem using Netbeans IDE.
but I am getting an error from nmake.

     Microsoft (R) Program Maintenance Utility Version 1.50
     Copyright (c) Microsoft Corp 1988-94. All rights reserved.

       cl -nologo -I. -I. -IC:/www/ruby/lib/ruby/1.8/i386-mswin32 -I. -
MD -Zi -O2b2xg- -G6 -c -Tcwin32/api.c
     'cl' is not recognized as an internal or external command,
     operable program or batch file.
     NMAKE : fatal error U1077: 'C:\WINDOWS\system32\cmd.exe' : return
code '0x1'
     Stop.

I have only just downloaded nmake in order to update and don't know
how to use it or what this operation is doing.

Does anybody have any pointers?

Thanks,

cl is the MS compiler for the C language. Normally, open source stuff
provides a windows binary. I just ran into a similar situation with
ruby-debug. The ruby-debug gem wants a specific version of the C
compiler. Exactly version 1200, which should be 12.0, I think.

fredistic