small fix

app/models/writing_conference.rb

@@ -105,7 +105,7 @@ class WritingConference
       
       pd_data = []
       fields_to_show.collect do |t|
-        if page.custom_string_field == "table"
+        if !page.nil? && page.custom_string_field == "table"
           case t
             when "paper_title"
               pd_data << { "data_title" => "<a href='#{OrbitHelper.url_to_plugin_show(p.to_param,'personal_conference')}' target='_blank'>#{p.paper_title}</a>" }