I have a custom page that copies items from one list in one site to another, and its failing with the exception above.

I tried checking the field using sharepoint  manager but I didnt find anything strange.  Tthe field where its failing its a managed metadata column



the strange thing its that the exception is shown when checking if the field[internalname] is != null


  

    foreach (SPListItem item in listItems)
                                {
    
                                    SPListItem targetItem = destinationList.Items.Add();
                                    foreach (SPField field in item.Fields)
                                    {
                                        if (!field.ReadOnlyField && field.InternalName != "Attachments")
                                        {
                                            if (item[field.InternalName] != null)
                                            {