Inserting Links crashes when address is .\

[LOVEJesus]

Using Windows 7 and ZIM 0.68, if I try to insert a link on ZIM by using the "links dialog" and I give as address ".\" (See attached picture), then Zim shows following crashing message.

See error message.

This is zim 0.68
Platform: nt
Locale: de_DE cp1252
FS encoding: mbcs
Python: (2, 7, 14, 'final', 0)
Gtk: (2, 24, 10)
Pygtk: (2, 24, 0)
No bzr version-info found

======= Traceback =======
  File "zim\gui\widgets.pyo", line 3211, in do_response
  File "zim\gui\pageview.pyo", line 6857, in do_response_ok
  File "zim\notebook\notebook.pyo", line 1107, in relative_filepath
  File "zim\newfs\base.pyo", line 366, in relpath
AttributeError: 'NoneType' object has no attribute 'pathnames'