anchor.diff:  	   <% else %>
   	     Your group
   	   <% end %>
  -            <% if @grouping.inviter == @current_user and !@grouping.is_valid? %>
  +            <% if !@grouping.nil? && @grouping.inviter == @current_user and !@grouping.is_valid? %>
   	    <%= link_to_remote I18n.t(:delete),:url => { :action => 'deletegroup', :id => @assignment.id, :grouping_id =>  @grouping.id },
   	    :html => {:title => "Delete this group", :class => "delete"},
   	    :confirm => "Are you sure you want to delete this group?"
  
positive.code:  </div>    
  </div>
  
  <% if @grouping.inviter == @current_user && !@assignment.instructor_form_groups %>
    <div id="invite_dialog">
      <h2>Invite</h2>
      <p>
  
negative.code: 	   </h3>
       
       <% # Display the URL of this group's repository if applicable %>
       <% if !@grouping.nil? && @grouping.group.repository_external_commits_only? %>
       <div class="sub_block"> 
         <h3>URL to your group's repository</h3>
  	     <p><%= h(@grouping.group.repository_external_access_url) %></p>
  