form validation again

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

@@ -9,6 +9,7 @@
     <div class="modal-header">
         <h3><%= t 'admin.file_upload' %></h3>
     </div>
+    <label class="control-label error" id="dyn_error"></label>
     <div class="modal-body form-horizontal">
         <div class="control-group">
             <label for="title" class="control-label error"><%= t 'admin.title' %></label>