No more edit possible

[EricDHH]

12.04 amd64
ii alacarte 0.13.2-2ubuntu easy GNOME menu editing tool

Alacarte has a "new entry" and "new menu" button on the right. When opened and moved to the right place these buttons do nothing but:
eric@agamemnon:~$ alacarte
`menu_proxy_module_load': /usr/bin/python: undefined symbol: menu_proxy_module_load
/usr/share/alacarte/Alacarte/MainWindow.py:53: GtkWarning: Failed to load type module: (null)

  self.tree.add_from_file(os.path.join(self.file_path, 'alacarte.ui'))
Traceback (most recent call last):
  File "/usr/share/alacarte/Alacarte/MainWindow.py", line 317, in on_new_item_button_clicked
    process = subprocess.Popen(['gnome-desktop-item-edit', file_path], env=os.environ)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] Datei oder Verzeichnis nicht gefunden
Traceback (most recent call last):
  File "/usr/share/alacarte/Alacarte/MainWindow.py", line 301, in on_new_menu_button_clicked
    process = subprocess.Popen(['gnome-desktop-item-edit', file_path], env=os.environ)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] Datei oder Verzeichnis nicht gefunden

Same with root:
eric@agamemnon:~$ sudo alacarte
Traceback (most recent call last):
  File "/usr/share/alacarte/Alacarte/MainWindow.py", line 317, in on_new_item_button_clicked
    process = subprocess.Popen(['gnome-desktop-item-edit', file_path], env=os.environ)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] Datei oder Verzeichnis nicht gefunden
Traceback (most recent call last):
  File "/usr/share/alacarte/Alacarte/MainWindow.py", line 301, in on_new_menu_button_clicked
    process = subprocess.Popen(['gnome-desktop-item-edit', file_path], env=os.environ)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] Datei oder Verzeichnis nicht gefunden

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: alacarte 0.13.2-2ubuntu4
ProcVersionSignature: Ubuntu 3.2.0-24.38-generic 3.2.16
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
CheckboxSubmission: 72ffaca291c05635776d4a13f9e644e4
CheckboxSystem: 32980ee028b29311fef8e195a759b031
Date: Thu May 17 10:37:52 2012
InstallationMedia: Ubuntu-Studio 11.04 "Natty Narwhal" - Release amd64 (20110426.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=de_DE:de_DE.UTF8:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=de_DE.utf8
 SHELL=/bin/bash
SourcePackage: alacarte
UpgradeStatus: No upgrade log present (probably fresh install)