Hello, there's certainly a monstrous error I don't see in :
<% for i in @news %>
  <% if dern_cat != i.categorie %>
   <% case i.categorie %>
   <% end %>
  <% end %>
<% end %>

I've removed all the code I could and don't understand why the case 
i.categorie produce a syntax error, unexpected tIDENTIFIER, expecting kWHEN

What is that syntax error ?

Thank you