Sample app got error when creating speaker profile

Environment:

Request Method: POST
Request URL: http://localhost:8000/speaker/create/

Django Version: 1.7.1
Python Version: 2.7.10
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.messages',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.staticfiles',
 'django.contrib.humanize',
 'bootstrapform',
 'pinax_theme_bootstrap',
 'account',
 'easy_thumbnails',
 'eventlog',
 'markitup',
 'metron',
 'reversion',
 'sitetree',
 'taggit',
 'timezones',
 'symposion',
 'symposion.boxes',
 'symposion.cms',
 'symposion.conference',
 'symposion.proposals',
 'symposion.reviews',
 'symposion.schedule',
 'symposion.speakers',
 'symposion.sponsorship',
 'symposion.teams',
 'symposiontest',
 'symposiontest.proposals']
Installed Middleware:
['django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'reversion.middleware.RevisionMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']

Traceback:
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  111.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/symposion/speakers/views.py" in speaker_create
  35.             speaker.save()
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/base.py" in save
  591.                        force_update=force_update, update_fields=update_fields)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/base.py" in save_base
  619.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/base.py" in _save_table
  700.             result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/base.py" in _do_insert
  733.                                using=using, raw=raw)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/manager.py" in manager_method
  92.                 return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/query.py" in _insert
  921.         return query.get_compiler(using=using).execute_sql(return_id)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
  919.             for sql, params in self.as_sql():
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in as_sql
  877.                 for obj in self.query.objs
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/markitup/fields.py" in pre_save
  96.         rendered = render_func(value.raw)
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/django/utils/functional.py" in _curried
  17.         return _curried_func(*(args + moreargs), **dict(kwargs, **morekwargs))
File "/home/miurahr/.pyenv/versions/pinax-proj-symposion/lib/python2.7/site-packages/symposion/markdown_parser.py" in parse
  14.     for token in parser.parseFragment(text).childNodes:

Exception Type: AttributeError at /speaker/create/
Exception Value: childNodes
pinax / pinax-project-symposion

Sample app got error when creating speaker profile #8
