Problem activate vocabulary

Hi, I think I found a bug, but it seems strange that nobody point it out before, since with it the module can't be used at all.
Anyway, the problem was that I couldn't set up any vocabulary to be used to tag users, because nothing was written in users_tag_vocabulary table from admin/settings/user_tags configuration page.
I looked at user_tags.module and found the following code at the beginning of user_tags_settings function:

  if ($_POST['edit']['user_tags_vocabulary_list']) {
    db_query('DELETE FROM {user_tags_vocabulary}');
    foreach ($_POST['edit']['user_tags_vocabulary_list'] as $vid) {
      db_query("INSERT INTO {user_tags_vocabulary} (vid) VALUES (%d)", $vid);
    }
  } 

I don't know what is the ['edit'] index. Anyway I simply removed it and now everything works.
In other words I replaced the above code with:

  if ($_POST['user_tags_vocabulary_list']) {
    db_query('DELETE FROM {user_tags_vocabulary}');
    foreach ($_POST['user_tags_vocabulary_list'] as $vid) {
      db_query("INSERT INTO {user_tags_vocabulary} (vid) VALUES (%d)", $vid);
    }
  }