title: Cannot complete the install because one or more required items could not be found
body: <p>I tried to install Green UML, it said:</p>
  
  <blockquote>
    <p>Cannot complete the install because one or more required items could not be found.<br>
        Software being installed: Green 3.5.0 (Green.feature.group 3.5.0)<br>
        Missing requirement: Green 3.5.0 (Green.feature.group 3.5.0) requires   'org.eclipse.core.boot 0.0.0' but it could not be found,</p>
  </blockquote>
  
  <p>How can I install <code>org.eclipse.core.boot 0.0.0</code>? I have tried many other UML tools and always got the same error. I am using <strong>Eclipse Juno</strong>. </p>