I use Fedora 17 with XFCE. When i'm trying to start alacarte never happens. Terminal output:

$ alacarte
Traceback (most recent call last):
  File "/usr/bin/alacarte", line 36, in <module>
    main()
  File "/usr/bin/alacarte", line 33, in main
    app.run()
  File "/usr/lib/python2.7/site-packages/Alacarte/MainWindow.py", line 64, in run
    self.loadMenus()
  File "/usr/lib/python2.7/site-packages/Alacarte/MainWindow.py", line 203, in loadMenus
    self.on_menu_tree_cursor_changed(menu_tree)
  File "/usr/lib/python2.7/site-packages/Alacarte/MainWindow.py", line 354, in on_menu_tree_cursor_changed
    self.loadItems(self.menu_store[menu_path][2], menu_path)
  File "/usr/lib/python2.7/site-packages/Alacarte/MainWindow.py", line 217, in loadItems
    for item, show in self.editor.getItems(menu):
  File "/usr/lib/python2.7/site-packages/Alacarte/MenuEditor.py", line 145, in getItems
    item = item_iter.get_separator()
AttributeError: 'TreeIter' object has no attribute 'get_separator'

$ rpm -q alacarte pygtk2
alacarte-0.13.4-4.fc17.noarch
pygtk2-2.24.0-4.fc17.i686

I've seen pygtk documentation. In really TreeIter has no get_separator function