UnicodeDecodeError: 'utf8' codec can't decode byte 0xd0 in position 0: invalid continuation byte

This is zim 0.52
Python version is sys.version_info(major=2, minor=7, micro=2, releaselevel='final', serial=0)
Gtk version is (2, 24, 6)
Pygtk version is (2, 24, 0)
Platform is posix
Zim revision is:
  branch: pyzim-trunk
  revision: 391 <email address hidden>
  date: 2011-04-28 20:09:07 +0200

======= Traceback =======
  File "/usr/lib/pymodules/python2.7/zim/gui/widgets.py", line 1912, in do_response
    destroy = self.do_response_ok()
  File "/usr/lib/pymodules/python2.7/zim/gui/__init__.py", line 2419, in do_response_ok
    tree = template.process_to_parsetree(self.ui.notebook, page)
  File "/usr/lib/pymodules/python2.7/zim/templates.py", line 358, in process_to_parsetree
    lines = self.process(notebook, page)
  File "/usr/lib/pymodules/python2.7/zim/templates.py", line 347, in process
    output = GenericTemplate.process(self, dict)
  File "/usr/lib/pymodules/python2.7/zim/templates.py", line 203, in process
    output = TextBuffer(self.tokens.process(dict))
  File "/usr/lib/pymodules/python2.7/zim/templates.py", line 386, in process
    output.extend(token.process(dict))
  File "/usr/lib/pymodules/python2.7/zim/templates.py", line 441, in process
    return [unicode(value).encode('utf-8')]
UnicodeDecodeError: 'utf8' codec can't decode byte 0xd0 in position 0: invalid continuation byte