facebook Friend list is not shown on my website if user log offs from facebook

Question

I'm using infinite_session to get the facebook session of user. I'm using facebooker plugin. for facebook website integration.

Situation is: if user is logged on my website in the first tab of browser & in the second tab user is logged on facebook, all the facebook friends are shown properly on my website.

But if user logs off from facebook, then facebook friend's page does not show a single facebook friends from facebook. Though I have infinite_session key & I have created the facebook session.

The code to render the facebook friends is:

<fb:serverfbml style="width:745px;">
  <script type="text/fbml">
      <fb:fbml>
      <fb:request-form 
    <%#*"/invitations/facebook_invitation"%>
  action="http://&lt;%= @http_host %>/facebook_connect/connect/?go_to=invitation"
  method="POST" invite="true"
    type="XXXXXXXXXXXXXXX"
    content="<fb:name uid=<%= current_facebook_user.to_i %> useyou='false' /> is a member of XXXXXXXXX and would like to share that experience with you. To register, simply click on the 'Register' button below.<fb:req-choice url='http://&lt;%= @http_host %>/user/signup' label='Register' />">
      <fb:multi-friend-selector showborder="true"
    actiontext="Invite your Facebook Friends to use XXXXXXXXXX"
    exclude_ids="<%= current_facebook_user.friends_with_this_app.map(&:id).join(',')%>"  />
      </fb:request-form>
      </fb:fbml>
  </script>
</fb:serverfbml>

How can I solve this problem? Thanks in advance.