Forum: Rails Engines failing to gem update

Hi, I keep on receiving the following error when I try to gem update:

Updating installed gems
Updating facebooker
Building native extensions.  This could take a while...
ERROR:  While executing gem ... (Gem::Installer::ExtensionBuildError)
    ERROR: Failed to build gem native extension.

c:/ruby/bin/ruby.exe extconf.rb update
creating Makefile

nmake
'nmake' is not recognized as an internal or external command,
operable program or batch file.


Gem files will remain installed in
c:/ruby/lib/ruby/gems/1.8/gems/json-1.1.3 for inspection.
Results logged to
c:/ruby/lib/ruby/gems/1.8/gems/json-1.1.3/ext/json/ext/parser/gem_make.out



Here is my rails installation info:
----------------------------------------
  - RUBYGEMS VERSION: 1.3.1
  - RUBY VERSION: 1.8.6 (2007-09-24 patchlevel 111) [i386-mswin32]
  - INSTALLATION DIRECTORY: c:/ruby/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: c:/ruby/bin/ruby.exe
  - EXECUTABLE DIRECTORY: c:/ruby/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-mswin32-60
  - GEM PATHS:
     - c:/ruby/lib/ruby/gems/1.8
     - c:/.gem/ruby/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://gems.rubyforge.org/


Any help will be appreciated!