Problem(Error) in ruby-on rails installtion

To install the ruby-on rails on my computer i used the following commands in terminal

1)sudo apt-get install build-essentail (completed successfully)

2)sudo apt-get install ruby-full (completed successfully)

3)Download the rubygems-1.3.7.tgz in download directory and the

      cd Downloads
                  sudo tar -xvzf rubygems-1.3.7.tgz
                  cd rubygems-1.3.7
         ruby setup.rb                                     (completed successfully)
  1. Then change directory as

                     cd /usr/bin
      Then typed

sudo gem install rails --version 2.3.2 --include-dependencies

After this command ,i got the following error

          amrit@amrit-desktop:~$ cd /usr/bin
              amrit@amrit-desktop:/usr/bin$ sudo gem install rails --version 2.3.2 --include-dependencies;
              [sudo] password for amrit:

             ERROR:  Loading command: install (LoadError)
       no such file to load -- zlib
               ERROR:  While executing gem ... (NameError)
               uninitialized constant Gem::Commands::InstallCommand

Please somebody help to resolve it

Thanks in advance

Maybe try sudo gem update --system and then sudo gem env to make sure that Gem sees the same Ruby you do when you do ruby -v.