cannot import name CachingParentsProvider

bzr: ERROR: exceptions.ImportError: cannot import name CachingParentsProvider

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 802, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 758, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 1032, in run
    possible_transports=possible_transports)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 127, in read_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1753, in get_master_branch
    possible_transports=possible_transports)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 128, in open
    possible_transports=possible_transports)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 572, in open
    return BzrDir.open_from_transport(t, _unsupported=_unsupported)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 609, in open_from_transport
    redirected)
  File "/usr/lib/python2.5/site-packages/bzrlib/transport/__init__.py", line 1661, in do_catching_redirections
    return action(transport)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 586, in find_format
    transport, _server_formats=_server_formats)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 1307, in find_format
    return format.probe_transport(transport)
  File "/home/adriano/.bazaar/plugins/svn/format.py", line 56, in probe_transport
    format = klass()
  File "/home/adriano/.bazaar/plugins/svn/format.py", line 49, in __init__
    from repository import SvnRepositoryFormat
  File "/home/adriano/.bazaar/plugins/svn/repository.py", line 23, in <module>
    from bzrlib.graph import CachingParentsProvider
ImportError: cannot import name CachingParentsProvider

bzr 1.0.0 on python 2.5.1.final.0 (linux2)
arguments: ['/usr/bin/bzr', 'up']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'pt_BR.UTF-8'
plugins:
  bzr_xmloutput /home/adriano/.bazaar/plugins/bzr_xmloutput [0.4.0]
  bzrtools /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.0.0]
  gtk /usr/lib/python2.5/site-packages/bzrlib/plugins/gtk [0.93.0]
  launchpad /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
  multiparent /usr/lib/python2.5/site-packages/bzrlib/plugins/multiparent.pyc [unknown]
  svn /home/adriano/.bazaar/plugins/svn [0.4.9]
*** Bazaar has encountered an internal error.
    Please report a bug at https://bugs.launchpad.net/bzr/+filebug
    including this traceback, and a description of what you
    were doing when the error occurred.