Error deleting entity

In the code below, I check the checkboxes in the ListView. When a check is checked the id assigned to that checkbox in the database, when I click again and uncheck it it should delete this id from a table in the database, however I am missing the following error:

  

"Deletion error, there is no column relationship with layout. could not   DELETE FROM LAYOUT WHERE ID =? "

foreach (ListViewItem x in lsvRecebeGrupoLayout.CheckedItems)
{
    int idlayout = Convert.ToInt32(x.SubItems[0].Text);
    lay = repolay.ConsultaPorId(idlayout);
    grupo.Id = idcbo;
    lay.GrupoLayout = grupo;

    if (x.Checked)
    {
        repolay.Alterar(lay);
    }

    if (e.Item.Checked == false)
    {
        repolay.Excluir(lay);
    }
}

Delete Method

public void Excluir(T entidade) {
    using(ISession session = FluentnHibernateHelper.OpenSession()) {
        using(ITransaction transacao = session.BeginTransaction()) {
            try {
                session.Delete(entidade);
                transacao.Commit();
            } catch(Exception ex) {
                if (!transacao.WasCommitted) {
                    transacao.Rollback();
                }
                throw new Exception("Erro de exclusão, há relação com um coluna de layout\n" + ex.Message);
            }
        }
    }
}