beef-xss and gems, please assist

[thepoor]

Hi all,

I was trying to install beef-xss. installation all good but when I ran ./beef I got: Could not find thin-1.6.1 in any of the sources
Run `bundle install` to install missing gems.

I trying to install thin, I got the below: I googled and tried all the methods out there but still unable to install thin. Please help, pretty please.

gem install thin
Building native extensions. This could take a while...
ERROR: Error installing thin:
ERROR: Failed to build gem native extension.

/usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from extconf.rb:2:in `<main>'


Gem files will remain installed in /var/lib/gems/1.9.1/gems/eventmachine-1.0.3 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/eventmachine-1.0.3/ext/gem_make.out

[thepoor]

Please disregard. I got it to work. I just removed gem and ruby then reinstall them.