Bazaar Explorer crash on "Open URL", svn

I tried to open a SVN repository using Open URL, svn//my.server.location/repo, and got this error -- which is a different one from #447846

bzr: ERROR: exceptions.AttributeError: 'QUIFactory' object has no attribute 'get_username'

Traceback (most recent call last):
  File "C:/Program Files (x86)/Bazaar/plugins\explorer\lib\explorer.py", line 1091, in callable_with_cleanup
  File "C:/Program Files (x86)/Bazaar/plugins\explorer\lib\explorer.py", line 1238, in _open_location_task
  File "C:/Program Files (x86)/Bazaar/plugins\explorer\lib\location.py", line 138, in __init__
  File "C:/Program Files (x86)/Bazaar/plugins\explorer\lib\location.py", line 143, in reopen_location
  File "bzrlib\bzrdir.pyo", line 990, in open_containing_tree_branch_or_repository
  File "bzrlib\bzrdir.pyo", line 898, in open_containing
  File "bzrlib\transport\__init__.pyo", line 1587, in get_transport
  File "bzrlib\transport\__init__.pyo", line 1610, in _try_transport_factories
  File "C:/Program Files (x86)/Bazaar/plugins\svn\errors.py", line 137, in convert
  File "C:/Program Files (x86)/Bazaar/plugins\svn\transport.py", line 303, in __init__
  File "C:/Program Files (x86)/Bazaar/plugins\svn\transport.py", line 269, in get
  File "C:/Program Files (x86)/Bazaar/plugins\svn\transport.py", line 212, in Connection
  File "subvertpy\ra.pyo", line 47, in RemoteAccess
  File "C:/Program Files (x86)/Bazaar/plugins\svn\auth.py", line 86, in get_svn_simple
  File "bzrlib\config.pyo", line 1203, in get_user
AttributeError: 'QUIFactory' object has no attribute 'get_username'

bzr 2.0.0 on python 2.5.4 (win32)
arguments: ['C:\\Program Files (x86)\\Bazaar\\bzr.exe', 'explorer']
encoding: 'cp1252', fsenc: 'mbcs', lang: None
plugins:
  bzrtools C:\Program Files (x86)\Bazaar\plugins\bzrtools [2.0.0]
  explorer C:\Program Files (x86)\Bazaar\plugins\explorer [0.8.2]
  launchpad C:\Program Files (x86)\Bazaar\plugins\launchpad [2.0.0]
  netrc_credential_store C:\Program Files (x86)\Bazaar\plugins\netrc_credential_store [2.0.0]
  qbzr C:\Program Files (x86)\Bazaar\plugins\qbzr [0.14.2]
  rebase C:\Program Files (x86)\Bazaar\plugins\rebase [0.5.3]
  svn C:\Program Files (x86)\Bazaar\plugins\svn [1.0.0]
  upload C:\Program Files (x86)\Bazaar\plugins\upload [1.0.0dev]
  xmloutput C:\Program Files (x86)\Bazaar\plugins\xmloutput [0.8.5]