Stacktrace (последний вызов снизу):

  File "django/core/handlers/base.py", line 112, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "django/db/transaction.py", line 431, in inner
    return func(*args, **kwargs)
  File "djangobb_forum/views.py", line 438, in show_topic
    post = reply_form.save()
  File "djangobb_forum/forms.py", line 122, in save
    self.save_attachment(post, self.cleaned_data['attachment'])
  File "djangobb_forum/forms.py", line 130, in save_attachment
    dir = os.path.join(settings.MEDIA_ROOT, forum_settings.ATTACHMENT_UPLOAD_TO)