使用UnicodeDecodeError升级到gae 1.7.6后，dev_appserver崩溃了

在我升级到gae 1.7.6之后，dev_appserver崩溃了，因为我有德语变音符号的文件夹 .
1.7.5没有问题！

2013-03-21 07:26:26 Running command: "['C:\\Python27\\pythonw.exe', 'C:\\Program Files (x86)\\Google\\google_appengine\\dev_appserver.py',
    '--skip_sdk_update_check=yes', '--port=8080', '--admin_port=8000', '--storage_path=C:/rugad', 'C:\\rugad\\gae']"
    INFO     2013-03-21 07:26:33,154 devappserver2.py:401] Skipping SDK update check.
    INFO     2013-03-21 07:26:33,276 api_server.py:152] Starting API server at: http://localhost:49981
    INFO     2013-03-21 07:26:33,283 dispatcher.py:98] Starting server "default" running at: http://localhost:8080
    INFO     2013-03-21 07:26:33,288 admin_server.py:117] Starting admin server at: http://localhost:8000
    Traceback (most recent call last):
      File "C:\Program Files (x86)\Google\google_appengine\_python_runtime.py", line 194, in 
        _run_file(__file__, globals())
      File "C:\Program Files (x86)\Google\google_appengine\_python_runtime.py", line 190, in _run_file
        execfile(script_path, globals_)
      File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\python\runtime.py", line 101, in 
        main()
      File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\python\runtime.py", line 78, in main
        sandbox.enable_sandbox(config)
      File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\python\sandbox.py", line 168, in enable_sandbox
        __import__('site')
      File "C:\Python27\lib\site.py", line 563, in 
        main()
      File "C:\Python27\lib\site.py", line 545, in main
        known_paths = addusersitepackages(known_paths)
      File "C:\Python27\lib\site.py", line 280, in addusersitepackages
        if ENABLE_USER_SITE and os.path.isdir(user_site):
      File "C:\Python27\lib\genericpath.py", line 41, in isdir
        st = os.stat(s)
      File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\python\stubs.py", line 268, in __call__
        if not FakeFile.is_file_accessible(path):
      File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\python\stubs.py", line 237, in is_file_accessible
        _is_path_in_directories(fixed_filename, FakeFile._allowed_dirs))
      File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\python\stubs.py", line 289, in _is_path_in_directories
        if os.path.commonprefix([fixed_path, fixed_parent]) == fixed_parent:
      File "C:\Python27\lib\genericpath.py", line 71, in commonprefix
        s1 = min(m)
    UnicodeDecodeError: 'ascii' codec can't decode byte 0xe4 in position 10: ordinal not in range(128)
    ERROR    2013-03-21 07:26:37,250 http_runtime.py:221] unexpected port response from runtime ['']; exiting the development server
    INFO     2013-03-21 07:26:37,315 api_server.py:517] Applying all pending transactions and saving the datastore
    INFO     2013-03-21 07:26:37,315 api_server.py:520] Saving search indexes
    2013-03-21 07:26:37 (Process exited with code 0)