Forum: Ferret installing ferret errors

After all day trying  to install ferret this is the result:
:( :( :(
C:\Documents and Settings\Gogolj>gem install ferret
Building native extensions.  This could take a while...
ERROR:  Error installing ferret:
        ERROR: Failed to build gem native extension.

G:/ruby/bin/ruby.exe extconf.rb install ferret
creating Makefile

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


Gem files will remain installed in
G:/ruby/lib/ruby/gems/1.8/gems/ferret-0.11.6
for inspection.
Results logged to
G:/ruby/lib/ruby/gems/1.8/gems/ferret-0.11.6/ext/gem_make.out

C:\Documents and Settings\Zoran>gem install ferret
Building native extensions.  This could take a while...
ERROR:  Error installing ferret:
        ERROR: Failed to build gem native extension.

G:/ruby/bin/ruby.exe extconf.rb install ferret
creating Makefile

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


Gem files will remain installed in
G:/ruby/lib/ruby/gems/1.8/gems/ferret-0.11.6
for inspection.
Results logged to
G:/ruby/lib/ruby/gems/1.8/gems/ferret-0.11.6/ext/gem_make.out

please help

solved :
gem install ferret --version 0.11.5

thanks