rake build error while installing vimpack

gistfile1.txt

amber@amber-Dell-System-L502X:~/vimpack$ rake build
/home/amber/.rvm/rubies/ruby-1.9.2-p320/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:247:in `to_specs': Could not find rake (>= 0) amongst [activemodel-3.0.20, activesupport-3.0.20, addressable-2.3.3, archive-tar-minitar-0.5.2, aruba-0.5.1, builder-2.1.2, childprocess-0.3.9, columnize-0.3.6, crack-0.3.2, cucumber-1.2.3, diff-lcs-1.2.1, enviro-0.0.5, faraday-0.8.6, faraday_middleware-0.9.0, ffi-1.4.0, gherkin-2.11.6, hashie-1.2.0, i18n-0.5.0, json-1.7.7, linecache19-0.5.12, mime-types-1.21, multi_json-1.6.1, multipart-post-1.2.0, nokogiri-1.5.6, octokit-1.0.7, rainbow-1.1.4, relish-0.6, rest-client-1.6.7, rspec-2.13.0, rspec-core-2.13.0, rspec-expectations-2.13.0, rspec-mocks-2.13.0, ruby-debug-base19-0.11.25, ruby-debug19-0.11.6, ruby_core_source-0.1.5, simplecov-0.7.1, simplecov-html-0.7.1, trollop-1.16.2, vcr-2.4.0, webmock-1.11.0, yajl-ruby-1.1.0] (Gem::LoadError)
	from /home/amber/.rvm/rubies/ruby-1.9.2-p320/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:256:in `to_spec'
	from /home/amber/.rvm/rubies/ruby-1.9.2-p320/lib/ruby/site_ruby/1.9.1/rubygems.rb:1231:in `gem'
	from /home/amber/.rvm/gems/ruby-1.9.2-p320@vimpack_dev/bin/rake:18:in `<main>'
	from /home/amber/.rvm/gems/ruby-1.9.2-p320@vimpack_dev/bin/ruby_noexec_wrapper:14:in `eval'
	from /home/amber/.rvm/gems/ruby-1.9.2-p320@vimpack_dev/bin/ruby_noexec_wrapper:14:in `<main>'