Eventmachine install error

Hi!
I get error, when i try to install eventmachine.

C:>gem install eventmachine
Building native extensions. This could take a while…
ERROR: Error installing eventmachine:
ERROR: Failed to build gem native extension.

C:/Ruby191/bin/ruby.exe extconf.rb
checking for rb_trap_immediate in ruby.h,rubysig.h… *** extconf.rb
failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.

Provided configuration options:
–with-opt-dir
–without-opt-dir
–with-opt-include
–without-opt-include=${opt-dir}/include
–with-opt-lib
–without-opt-lib=${opt-dir}/lib
–with-make-prog
–without-make-prog
–srcdir=.
–curdir
–ruby=C:/Ruby191/bin/ruby
C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:364:in try_do': The complier failed to generate an executable file. (RuntimeError) You have to install development tools first. from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:427:intry_compile’
from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:545:in try_var' from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:793:inblock in
have_var’
from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:670:in block in checking_for' from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:276:inblock (2 levels)
in postpone’
from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:250:in open' from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:276:inblock in
postpone’
from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:250:in open' from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:272:inpostpone’
from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:669:in checking_for' from C:/Ruby191/lib/ruby/1.9.1/mkmf.rb:792:inhave_var’
from extconf.rb:16:in `’

Gem files will remain installed in
C:/Ruby191/lib/ruby/gems/1.9.1/gems/eventmachine-0.12.10 for inspection.
Results logged to
C:/Ruby191/lib/ruby/gems/1.9.1/gems/eventmachine-0.12.10/ext/gem_make.out

Help me please!

Read the output. It suggests you to look into
C:/Ruby191/lib/ruby/gems/1.9.1/gems/eventmachine-0.12.10/ext/gem_make.out.

Problem solved!
Success way:

  1. install DevKit
    https://github.com/oneclick/rubyinstaller/wiki/development-kit
  2. gem install eventmachine --pre