關於 VERSION: 2.5.0-dev-7 發佈後的出錯信息

[guokb]

我是昨天晚上從 https://github.com/livid/v2ex 這裏用git clone的一份，
檔案里只按照( http://www.v2ex.com/cn/index.html )改了下 app.yaml 和 config.py 中自己的部分
但是用 GAE sdk的 lanucher-> deploy後，「首頁」僅僅是看到了一會兒，稍候就報告下面的信息：

Traceback (most recent call last):
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/_webapp25.py", line 710, in __call__
handler.get(*groups)
File "/base/data/home/apps/kooclass/3.362528604301743683/main.py", line 135, in get
home_rendered = template.render(path, template_values)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/template.py", line 92, in render
return t.render(Context(template_dict))
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/template.py", line 128, in wrap_render
return orig_render(context)
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/__init__.py", line 168, in render
return self.nodelist.render(context)
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/__init__.py", line 705, in render
bits.append(self.render_node(node, context))
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/__init__.py", line 718, in render_node
return(node.render(context))
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/defaulttags.py", line 122, in render
nodelist.append(node.render(context))
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/__init__.py", line 767, in render
output = self.filter_expression.resolve(context)
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/__init__.py", line 563, in resolve
obj = resolve_variable(self.var, context)
File "/base/python_runtime/python_lib/versions/third_party/django-0.96/django/template/__init__.py", line 650, in resolve_variable
current = getattr(current, bits[0])
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 3692, in __get__
instance = get(reference_id)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 1537, in get
return get_async(keys, **kwargs).get_result()
File "/base/python_runtime/python_lib/versions/1/google/appengine/api/apiproxy_stub_map.py", line 604, in get_result
return self.__get_result_hook(self)
File "/base/python_runtime/python_lib/versions/1/google/appengine/datastore/datastore_rpc.py", line 1459, in __get_hook
entities = rpc.user_data(entities)
File "/base/python_runtime/python_lib/versions/1/google/appengine/api/datastore.py", line 600, in local_extra_hook
return extra_hook(result)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 1507, in extra_hook
model = cls1.from_entity(entity)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 1442, in from_entity
return cls(None, _from_entity=entity, **entity_values)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 974, in __init__
prop.__set__(self, value)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 614, in __set__
value = self.validate(value)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 3214, in validate
value = super(IntegerProperty, self).validate(value)
File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", line 641, in validate
raise BadValueError('Property %s is required' % self.name)
BadValueError: Property notification_position is required

雖然首頁變成上面這樣子，然而，後臺的「記事本」 ，「設置」 ，「附近」 這幾個功能正常，
由於我是一名代碼盲，只有請求V2上折騰過或熟悉PB的朋友們幫忙看看了。 多謝先！

補充： 我的機器環境
。 win xp
。 app engine sdk 1.7.2 和 python 2.7

[guokb]

咦，之前已經有朋友也出現類似問題( t/43231 )，可是還沒有答案。

自己搜了一下，但 stackoverflow.com 上找的有些e文還是看不懂，恰哈 @keakon 的這篇「db.Property机制解析」（ http://www.keakon.net/2010/11/01/db.Property%E6%9C%BA%E5%88%B6%E8%A7%A3%E6%9E%90 ) 好彩是中文，可對於我這個代碼盲的人來說，也不知是哪裡能找正確的辦法。

自己用 gedit 打開 mapreduce 文件夾下 model.py 的源碼，發現大致從137行-154行跟上面提到的情形有些類似，但我還是不能肯定，所以還是請求v2里的達人給指點一下，結合上面的出錯信息，改如何着手呢？

多謝各位啦！