pressing on magnifier in the search field for the 2nd time causes error

[YK]

InterfaceError: Error binding parameter 0 - probably unsupported type.

This is zim 0.60
Python version is sys.version_info(major=2, minor=7, micro=6, releaselevel='final', serial=0)
Gtk version is (2, 24, 23)
Pygtk version is (2, 24, 0)
Platform is posix
Zim revision is:
  branch: pyzim-trunk
  revision: 672 <email address hidden>
  date: 2013-04-30 19:27:20 +0200

======= Traceback =======
  File "/usr/lib/python2.7/dist-packages/zim/gui/searchdialog.py", line 91, in _search
    self.results_treeview.search(string)
  File "/usr/lib/python2.7/dist-packages/zim/gui/searchdialog.py", line 176, in search
    self.selection.search(self.query, callback=self._search_callback)
  File "/usr/lib/python2.7/dist-packages/zim/search.py", line 253, in search
    self.update(self._process_group(query.root, selection, callback))
  File "/usr/lib/python2.7/dist-packages/zim/search.py", line 352, in _process_group
    contentterms, results, scope, group.operator, callback)
  File "/usr/lib/python2.7/dist-packages/zim/search.py", line 496, in _process_content
    for page in generator:
  File "/usr/lib/python2.7/dist-packages/zim/notebook.py", line 1953, in walk
    for p in self.index.walk(path):
  File "/usr/lib/python2.7/dist-packages/zim/index.py", line 1223, in _walk
    for grandchild in self._walk(child, childpath):
  File "/usr/lib/python2.7/dist-packages/zim/index.py", line 1216, in _walk
    cursor.execute('select * from pages where parent = ? order by sortkey, basename', (path.id,))
InterfaceError: Error binding parameter 0 - probably unsupported type.