Sqlite transaction in Qt

I am doing sql transaction in qt.

bool X::save()
{
  mDatabase.transaction();

  if (!saveHeader())
  {
       mDatabase.rollback();
       return false;
  }

  if (!saveBody())
  {
       mDatabase.rollback();
       return false;
  }

  mDatabase.commit();     
  return true;
}

My commit returns fails an returns "cannot commit - no transaction is active Unable to commit transaction"

I have SELECT and DELETE query in the functions. But I do query.clear(); after execution.

Still I get this error. Someone knows why...