Bug: Webadmin KeyError 'nav'

[wmoore]

If I logout (to clear request.session) then log in as root and go to webadmin/experimenters/

This is on latest develop (with 8610 merged)

Request Method: GET
Request URL: http://howe.openmicroscopy.org.uk/webadmin/experimenters/

Django Version: 1.3.1
Python Version: 2.6.5
Installed Applications:
['django.contrib.staticfiles',
 'django.contrib.markup',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'omeroweb.feedback',
 'omeroweb.webadmin',
 'omeroweb.webclient',
 'omeroweb.webgateway',
 'omeroweb.webtest',
 'omeroweb.webredirect']
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware')


Traceback:
File "/home/hudson/hudson/workspace/OMERO-merge-blue/src/dist/lib/python/django/core/handlers/base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/hudson/hudson/workspace/OMERO-merge-blue/src/dist/lib/python/omeroweb/decorators.py" in wrapped
  313.             retval = f(request, *args, **kwargs)
File "/home/hudson/hudson/workspace/OMERO-merge-blue/src/dist/lib/python/omeroweb/decorators.py" in wrapper
  347.             context = f(request, *args, **kwargs)
File "/home/hudson/hudson/workspace/OMERO-merge-blue/src/dist/lib/python/omeroweb/webadmin/views.py" in experimenters
  299.     context = {'nav':request.session['nav'], 'info':info, 'experimenterList':experimenterList}
File "/home/hudson/hudson/workspace/OMERO-merge-blue/src/dist/lib/python/django/contrib/sessions/backends/base.py" in __getitem__
  47.         return self._session[key]

Exception Type: KeyError at /webadmin/experimenters/
Exception Value: 'nav'