Confused about Gtk2::TreeView::get_model()

[Joerg Mueller <jfm ram-brand de>]

Hi Folks,

In a little app I wrote recently, there is a TreeView widget displaying
a list of machines. I'm using Gtk2 version 1.00. Since the list has to
be reordered via "Up" and "Down" ButtonWidgets I'd like to access the
TreeModel and its method "nth_child".

C API method definition for tree_model:
gboolean    gtk_tree_model_iter_nth_child   (GtkTreeModel *tree_model,
                                             GtkTreeIter *iter,
                                             GtkTreeIter *parent,
                                             gint n);
Example code from my app:
...
my $treeview = Gtk2::TreeView->new($listStore);
my $model = $treeview->get_model;
my $iter = $treeview->get_selection;
# GET INDEX No IN LIST FROM CURRENT SELECTED ENTRY   
my $path = $model->get_string_from_iter( $iter);
my $previous = $path - 1;               
my $previous_entry =  $model->get_nth_child( $previous_no ); #<< THROWS
EXCEPTION
$model->move_before( $iter, $previous_entry);
print Dumper($treemodel);
...             

STDOUT shows "Gtk2::TreeStore=HASH(0x8700210)" ?!?

This is wrong according to the C API definitions:
GtkTreeModel* gtk_tree_view_get_model       (GtkTreeView *tree_view);


Did I miss something or got it all wrong?

-- 
Joerg Mueller <jfm ram-brand de>