Rendering of Django Forms with errors

What steps will reproduce the problem?
We have an application "guestbook". Now we have a small problem with rendering 
forms. In the template file we have a code with this part
{{ form }}
this is equal to
{{ form.as_table }}
This command should render form in html table.

What is the expected output? What do you see instead?
ACTUAL RESULT. We have see correct form only on the first page loading. On all 
next page reloads we have see error message (see traceback below).

EXPECTED RESULT. We should see rendered form without error messages.

Please use labels and text to provide additional information.
Traceback (most recent call last):
  File "/home/anton/workspace/gaeframework/src/gae/webapp.py", line 104, in load_app
    return app_action(self, **params)
  File "/home/anton/workspace/gaeframework/src/apps/guestbook/controllers.py", line 22, in create_item
    return app.render('guestbook/create_item', {'form': form})
  File "/home/anton/workspace/gaeframework/src/gae/webapp.py", line 226, in render
    return template.render(path, values, self.debug)
  File "/home/anton/workspace/gaeframework/src/gae/template.py", line 17, in render
    return t.render(Context(template_dict))
  File "/home/anton/workspace/gaeframework/src/gae/template.py", line 65, in wrap_render
    return orig_render(context)
  File "gae/lib/django.zip/django/template/__init__.py", line 173, in render
  File "gae/lib/django.zip/django/template/__init__.py", line 167, in _render
  File "gae/lib/django.zip/django/template/__init__.py", line 796, in render
  File "gae/lib/django.zip/django/template/debug.py", line 72, in render_node
  File "gae/lib/django.zip/django/template/loader_tags.py", line 125, in render
  File "gae/lib/django.zip/django/template/__init__.py", line 167, in _render
  File "gae/lib/django.zip/django/template/__init__.py", line 796, in render
  File "gae/lib/django.zip/django/template/debug.py", line 72, in render_node
  File "gae/lib/django.zip/django/template/loader_tags.py", line 125, in render
  File "gae/lib/django.zip/django/template/__init__.py", line 167, in _render
  File "gae/lib/django.zip/django/template/__init__.py", line 796, in render
  File "gae/lib/django.zip/django/template/debug.py", line 72, in render_node
  File "gae/lib/django.zip/django/template/loader_tags.py", line 62, in render
  File "gae/lib/django.zip/django/template/__init__.py", line 796, in render
  File "gae/lib/django.zip/django/template/debug.py", line 72, in render_node
  File "gae/lib/django.zip/django/template/loader_tags.py", line 62, in render
  File "gae/lib/django.zip/django/template/__init__.py", line 796, in render
  File "gae/lib/django.zip/django/template/debug.py", line 72, in render_node
  File "gae/lib/django.zip/django/template/debug.py", line 91, in render
  File "gae/lib/django.zip/django/utils/encoding.py", line 66, in force_unicode
  File "gae/lib/django.zip/django/forms/forms.py", line 95, in __unicode__
  File "gae/lib/django.zip/django/forms/forms.py", line 217, in as_table
  File "gae/lib/django.zip/django/forms/forms.py", line 162, in _html_output
  File "gae/lib/django.zip/django/utils/encoding.py", line 66, in force_unicode
TemplateSyntaxError: Caught TypeError while rendering: coercing to Unicode: 
need string or buffer, instance found
Original issue reported on code.google.com by anton.danilchenko on 26 Jan 2011 at 8:46
google-code-export / gaeframework

Rendering of Django Forms with errors #2
