title: while executing gem ... (ArgumentError) unknown encoding name - CP720
body: <p>I got now this strange error </p>
  
  <pre><code>while executing gem ... (ArgumentError)
  unknown encoding name - CP720
  </code></pre>
  
  <p>When I want to run any gem commands  such as</p>
  
  <pre><code>   gem install rubygems-update
  </code></pre>
  
  <p>so when I goggled it  I found some one suggest to use this commands to Change encoding to 1252</p>
  
  <pre><code>C:\DevKit&gt; chcp 1252
  c:\DevKit&gt; ruby dk.rb init  
  </code></pre>
  
  <p>but after I used it I still got the same error , so <strong>how i can solve this issue</strong> ?????</p>
  
  <p>Note : I'm using windows 7</p>