Now that sextante is in core os.path.dirname(file) returns this error:

Traceback (most recent call last):
  File "/usr/local/share/qgis/python/qgis/utils.py", line 188, in startPlugin
    plugins[packageName] = package.classFactory(iface)
  File "/usr/local/share/qgis/python/plugins/sextante/__init__.py", line 46, in classFactory
    return SextantePlugin(iface)
  File "/usr/local/share/qgis/python/plugins/sextante/SextantePlugin.py", line 56, in __init__
    Sextante.initialize()
  File "/usr/local/share/qgis/python/plugins/sextante/core/Sextante.py", line 135, in initialize
    Sextante.modeler.initializeSettings();
  File "/usr/local/share/qgis/python/plugins/sextante/modeler/ModelerAlgorithmProvider.py", line 49, in initializeSettings
    SextanteConfig.addSetting(Setting(self.getDescription(), ModelerUtils.MODELS_FOLDER, "Models folder", ModelerUtils.modelsFolder()))
  File "/usr/local/share/qgis/python/plugins/sextante/modeler/ModelerUtils.py", line 41, in modelsFolder
    mkdir(folder)
  File "/usr/local/share/qgis/python/plugins/sextante/core/SextanteUtils.py", line 87, in mkdir
    os.mkdir(newdir)
OSError: [Errno 13] Permesso negato: '/usr/local/share/qgis/python/plugins/sextante/modeler/models'