Getting the SimpleTextEditor to work

Hi, I'm trying the the Simple Text Editor (posted by Wim Stockman at http://gtk.php.net/wiki/CodeSnippets/SimpleTextEditor). However, only partial success in making it work. I've downloaded the Windows package and am trying to make the program be GTK2. To get the actual text to save, I have this: $start = new GtkTextIter (); ... $text = $this->textbuf->get_text ($start, $end, true); where it seems $start and $end need to be GtkTextIter's. But, it won't allow me to instantiate these! I get "PHP Fatal error: Class GtkTextIter cannot be instantiated directly ...". I had previously tried to put NIL for the first two args to get_text but it insisted these args had to be of class GtkTextIter. Can someone suggest what I should try next or point me at some docs - I haven't been able to find very much. Thanks -- tim -- Tim