404 for pages and asset column error

app/controllers/pages_controller.rb

@@ -9,16 +9,19 @@ class PagesController < ApplicationController
     end
   end
   
-  def show    
-    item = Item.first(:conditions => {:full_name => params[:page_name]})
-    case item._type
-      when 'Page'
-        @page = item
-        render_liquid_page
-      when 'Link'
-        redirect_to "http://#{item[:url]}"
+  def show  
+    begin  
+      item = Item.first(:conditions => {:full_name => params[:page_name]})
+      case item._type
+        when 'Page'
+          @page = item
+          render_liquid_page
+        when 'Link'
+          redirect_to "http://#{item[:url]}"
+      end
+    rescue
+      render :file => "#{Rails.root}/public/404.html", :status => :not_found
     end
-        
   end
   
 end

app/views/admin/assets/index.html.erb

@@ -12,7 +12,7 @@
       <th><%= t('admin.description') %></th>
       <th><%= t('admin.format') %></th>
       <th><%= t('admin.orig_upload_file') %></th>
-      <th><%= t('admin.file_name') %></th>
+      <th><%= t('admin.file_size') %></th>
       <th><%= t('admin.action') %></th>
   </tr>