authentication.conf with german "umlaut" gives a traceback

Show Log crashes, if the line:

#test ÄäÖöÜüß

is present in file authentication.conf. All is O.K. if this line is deleted. I got the following Exeption, when i use the right mouse key and "Show Log". If I click on the clock Symbol on the main window, the "Show Log Window" disapears without any message.

bzr: ERROR: exceptions.UnicodeDecodeError: 'utf8' codec can't decode bytes in position 6-7: invalid data

Traceback (most recent call last):
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\trace.py", line 300, in reports_exception_decorate
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\log.py", line 231, in load
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\logwidget.py", line 199, in load_branch
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\loggraphprovider.py", line 322, in open_branch
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\loggraphprovider.py", line 297, in branch_label
  File "bzrlib\branch.pyo", line 248, in _get_nick
  File "bzrlib\decorators.pyo", line 140, in read_locked
  File "bzrlib\branch.pyo", line 2694, in get_master_branch
  File "bzrlib\branch.pyo", line 167, in open
  File "bzrlib\bzrdir.pyo", line 911, in open
  File "bzrlib\bzrdir.pyo", line 941, in open_from_transport
  File "bzrlib\transport\__init__.pyo", line 1657, in do_catching_redirections
  File "bzrlib\bzrdir.pyo", line 928, in find_format
  File "bzrlib\bzrdir.pyo", line 1949, in find_format
  File "bzrlib\bzrdir.pyo", line 1959, in probe_transport
  File "bzrlib\transport\sftp.pyo", line 435, in get_bytes
  File "bzrlib\transport\sftp.pyo", line 425, in get
  File "bzrlib\transport\sftp.pyo", line 397, in _get_sftp
  File "bzrlib\transport\sftp.pyo", line 389, in _create_connection
  File "bzrlib\transport\ssh.pyo", line 321, in connect_sftp
  File "bzrlib\transport\ssh.pyo", line 317, in _connect
  File "bzrlib\transport\ssh.pyo", line 543, in _paramiko_auth
  File "bzrlib\config.pyo", line 1215, in get_password
  File "bzrlib\config.pyo", line 1043, in get_credentials
  File "bzrlib\config.pyo", line 986, in _get_config
  File "bzrlib\config.pyo", line 144, in ConfigObj
  File "bzrlib\util\configobj\configobj.pyo", line 1223, in __init__
  File "bzrlib\util\configobj\configobj.pyo", line 1276, in _load
  File "bzrlib\util\configobj\configobj.pyo", line 1412, in _handle_bom
  File "bzrlib\util\configobj\configobj.pyo", line 1472, in _decode
  File "encodings\utf_8.pyo", line 16, in decode
UnicodeDecodeError: 'utf8' codec can't decode bytes in position 6-7: invalid data

bzr 2.2.1 on python 2.6.4 (win32)
arguments: ['C:\\Program Files (x86)\\Bazaar\\bzrw.exe', 'explorer']
encoding: 'cp1252', fsenc: 'mbcs', lang: None
plugins:
  bzrtools C:\Program Files (x86)\Bazaar\plugins\bzrtools [2.2.0]
  colo C:\Program Files (x86)\Bazaar\plugins\colo [0.1.0]
  explorer C:\Program Files (x86)\Bazaar\plugins\explorer [1.1.1]
  fastimport C:\Program Files (x86)\Bazaar\plugins\fastimport [0.9.0dev]
  launchpad C:\Program Files (x86)\Bazaar\plugins\launchpad [2.2.1]
  loom C:\Program Files (x86)\Bazaar\plugins\loom [2.2.1dev]
  netrc_credential_store C:\Program Files (x86)\Bazaar\plugins\netrc_credential_store [2.2.1]
  news_merge C:\Program Files (x86)\Bazaar\plugins\news_merge [2.2.1]
  pipeline C:\Program Files (x86)\Bazaar\plugins\pipeline [unknown]
  qbzr C:\Program Files (x86)\Bazaar\plugins\qbzr [0.19.2]
  rewrite C:\Program Files (x86)\Bazaar\plugins\rewrite [0.6.1]
  svn C:\Program Files (x86)\Bazaar\plugins\svn [1.0.4]
  upload C:\Program Files (x86)\Bazaar\plugins\upload [1.0.0dev]
  xmloutput C:\Program Files (x86)\Bazaar\plugins\xmloutput [0.8.6]