exception when deleting page

[smu]

Steps to reproduce:

1. create a new page
2. insert some text and save the page
3. try to delete the oage
4. an exception window is shown: "TypeError: walk() got an unexpected keyword argument 'followlinks'"
(5. after closing this exception window, the next try so delete the page works fine.)

zim -D
INFO: This is zim 0.47
DEBUG: Python version is (2, 5, 2, 'final', 0)
DEBUG: Gtk version is (2, 18, 6)
DEBUG: Pygtk version is (2, 12, 1)
...
DEBUG: Action: new_page
DEBUG: Opening dialog "New Page - Zim"
DEBUG: Dialog response OK
DEBUG: Found template '_New' for <FileStorePage: Test>
INFO: Loading template from: /usr/src/zim/data/templates/wiki/_New.txt
DEBUG: Saving page: <FileStorePage: Stuff>
DEBUG: Wrote /home/smu/Dropbox/zim/Notes/Stuff.txt
INFO: Open page: <FileStorePage: Test> (<FileStorePage: Test>)
DEBUG: Closed dialog "New Page"
DEBUG: Wrote /home/smu/Dropbox/zim/Notes/.zim/state.conf
DEBUG: Action: save_page
DEBUG: Saving page: <FileStorePage: Test>
DEBUG: Wrote /home/smu/Dropbox/zim/Notes/Test.txt
DEBUG: Action: delete_page
DEBUG: Pageindex has focus
DEBUG: Opening dialog "Delete Page - Zim"
DEBUG: Dialog response OK
DEBUG: Opening ProgressBarDialog
INFO: Remove file: /home/smu/Dropbox/zim/Notes/Test.txt
INFO: Remove file tree: /home/smu/Dropbox/zim/Notes/Test
DEBUG: Running ErrorDialog
ERROR: walk() got an unexpected keyword argument 'followlinks'
Traceback (most recent call last):
  File "/usr/src/zim/zim/gui/__init__.py", line 2317, in do_response_ok
    self.ui.notebook.delete_page(self.path, update_links, callback)
  File "/usr/src/zim/zim/notebook.py", line 1092, in delete_page
    store.delete_page(path)
  File "/usr/src/zim/zim/stores/files.py", line 134, in delete_page
    dir.remove_children()
  File "/usr/src/zim/zim/fs.py", line 633, in remove_children
    for root, dirs, files in os.walk(self.encodedpath, topdown=False, followlinks=False):
TypeError: walk() got an unexpected keyword argument 'followlinks'