AttributeError: 'NoneType' object has no attribute 'get_path_url' after enabling ContextMenuPlugin.*

[Matthew.Wild@…]

After installing and enabling the ContextMenuPlugin and looking at the 'Browse Source' page, I get this error

Trac detected an internal error:
AttributeError: 'NoneType' object has no attribute 'get_path_url'

The trace is

File "build/bdist.linux-x86_64/egg/trac/web/main.py", line 511, in _dispatch_request
  dispatcher.dispatch(req)
File "build/bdist.linux-x86_64/egg/trac/web/main.py", line 258, in dispatch
  content_type)
File "build/bdist.linux-x86_64/egg/trac/web/chrome.py", line 840, in render_template
  stream |= self._filter_stream(req, method, filename, stream, data)
File "/usr/lib/python2.7/site-packages/genshi/core.py", line 132, in __or__
  return Stream(_ensure(function(self)), serializer=self.serializer)
File "build/bdist.linux-x86_64/egg/trac/web/chrome.py", line 991, in inner
  data)
File "/usr/local/lib/python2.7/site-packages/ContextMenuPlugin-0.2dev_r11870-py2.7.egg/contextmenu/contextmenu.py", line 150, in filter_stream
  content = SubversionLink(self.env).get_content(req, data['path'], stream, data)
File "/usr/local/lib/python2.7/site-packages/ContextMenuPlugin-0.2dev_r11870-py2.7.egg/contextmenu/contextmenu.py", line 89, in get_content
  return tag.a(_('Subversion'), href=repos.get_path_url(path, None))

System information:

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.4 (KHTML, like Gecko) Chrome/22.0.1229.79 Safari/537.4

Trac	0.12.2
Babel	0.9.5
Genshi	0.6
mod_wsgi	3.3 (WSGIProcessGroup WSGIApplicationGroup %{GLOBAL})
pysqlite	2.6.0
Python	2.7 (r27:82500, Aug 07 2010, 16:54:59) [GCC]
setuptools	0.6
SQLite	3.7.5
Subversion	1.6.19 (r1383947)
jQuery	1.4.2

Enabled plugins:

Attachment-Policy-Plugin	0.1.0	/usr/local/lib/python2.7/site-packages/Attachment_Policy_Plugin-0.1.0-py2.7.egg
ContextMenuPlugin	0.2dev-r11870	/usr/local/lib/python2.7/site-packages/ContextMenuPlugin-0.2dev_r11870-py2.7.egg
FootNoteMacro	1.03-r10434	/usr/local/lib/python2.7/site-packages/FootNoteMacro-1.03_r10434-py2.7.egg
graphviz	0.7.5	/usr/local/lib/python2.7/site-packages/graphviz-0.7.5-py2.7.egg
IniAdmin	0.2-r10454	/usr/local/lib/python2.7/site-packages/IniAdmin-0.2_r10454-py2.7.egg
OverlayView	0.12.0.3	/usr/local/lib/python2.7/site-packages/OverlayView-0.12.0.3-py2.7.egg
TagPublic	0.0.1	/usr/local/lib/python2.7/site-packages/TagPublic-0.0.1-py2.7.egg
TicketGuidelinesPlugin	0.1-r514	/usr/local/lib/python2.7/site-packages/TicketGuidelinesPlugin-0.1_r514-py2.7.egg
TracAccountManager	0.3.2	/usr/local/lib/python2.7/site-packages/TracAccountManager-0.3.2-py2.7.egg
TracMasterTickets	3.0.2	/usr/local/lib/python2.7/site-packages/TracMasterTickets-3.0.2-py2.7.egg
TracNav	4.1	/usr/local/lib/python2.7/site-packages/TracNav-4.1-py2.7.egg
TracPermRedirect	2.0	/usr/local/lib/python2.7/site-packages/TracPermRedirect-2.0-py2.7.egg
TracSectionEditPlugin	0.2.6-r11208	/usr/local/lib/python2.7/site-packages/TracSectionEditPlugin-0.2.6_r11208-py2.7.egg
TracSubTicketsPlugin	0.1.0	/usr/local/lib/python2.7/site-packages/TracSubTicketsPlugin-0.1.0-py2.7.egg
TracTags	0.6	/usr/local/lib/python2.7/site-packages/TracTags-0.6-py2.7.egg
TracWikiPrintPlugin	1.9.2	/usr/local/lib/python2.7/site-packages/TracWikiPrintPlugin-1.9.2-py2.7.egg
TracWysiwyg	0.12.0.4-r11158	/usr/local/lib/python2.7/site-packages/TracWysiwyg-0.12.0.4_r11158-py2.7.egg