bzr: ERROR: documents is not an index of type <class 'bzrlib.index.GraphIndex'>.

I get the following on every commit and then need to do a bzr up to bring the tree back into order.

ii bzr-search 1.7.0~bzr70-1 search plugin for Bazaar
ii bzr 2.0.0-1~bazaar1~karmic1 easy to use distributed version control system

johnf@zoot:~/dev/vquence/metrics/trunk$ BZR_PDB=1 bzr commit -m "test"
Committing to: bzr://bzr.team.vquence.com/devel/metrics/trunk/
modified README
bzr: ERROR: documents is not an index of type <class 'bzrlib.index.GraphIndex'>.
**** entering debugger
> /usr/lib/python2.6/dist-packages/bzrlib/index.py(516)_read_prefix()
-> raise errors.BadIndexFormatSignature(self._name, GraphIndex)
(Pdb) bt
  /usr/lib/python2.6/dist-packages/bzrlib/commands.py(842)exception_to_return_code()
-> return the_callable(*args, **kwargs)
  /usr/lib/python2.6/dist-packages/bzrlib/commands.py(1037)run_bzr()
-> ret = run(*run_argv)
  /usr/lib/python2.6/dist-packages/bzrlib/commands.py(654)run_argv_aliases()
-> return self.run(**all_cmd_args)
  /usr/lib/python2.6/dist-packages/bzrlib/builtins.py(3051)run()
-> exclude=safe_relpath_files(tree, exclude))
  /usr/lib/python2.6/dist-packages/bzrlib/decorators.py(192)write_locked()
-> result = unbound(self, *args, **kwargs)
  /usr/lib/python2.6/dist-packages/bzrlib/workingtree_4.py(197)commit()
-> result = WorkingTree3.commit(self, message, revprops, *args, **kwargs)
  /usr/lib/python2.6/dist-packages/bzrlib/decorators.py(192)write_locked()
-> result = unbound(self, *args, **kwargs)
  /usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py(228)commit()
-> *args, **kwargs)
  /usr/lib/python2.6/dist-packages/bzrlib/commit.py(396)commit()
-> self.branch.set_last_revision_info(new_revno, self.rev_id)
  /usr/lib/python2.6/dist-packages/bzrlib/decorators.py(192)write_locked()
-> result = unbound(self, *args, **kwargs)
  /usr/lib/python2.6/dist-packages/bzrlib/branch.py(2508)set_last_revision_info()
-> self._run_post_change_branch_tip_hooks(old_revno, old_revid)
  /usr/lib/python2.6/dist-packages/bzrlib/branch.py(1081)_run_post_change_branch_tip_hooks()
-> hook(params)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/__init__.py(59)auto_index_branch()
-> search_index.index_branch(result.branch, result.new_revid)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(321)index_branch()
-> self.index_revisions(branch, revs_to_index)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(336)index_revisions()
-> outer_bar)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(384)_index_revisions()
-> self._add_index(builder)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(459)_add_index()
-> self._add_index(combiner, to_remove=components, allow_pack=False)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(397)_add_index()
-> self._upload_transport)
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(1264)upload_index()
-> return self.combine()
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(1235)combine()
-> self._copy_documents()
  /usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py(1151)_copy_documents()
-> for node in component.document_index.iter_all_entries():
  /usr/lib/python2.6/dist-packages/bzrlib/index.py(505)iter_all_entries()
-> self._buffer_all()
  /usr/lib/python2.6/dist-packages/bzrlib/index.py(433)_buffer_all()
-> self._read_prefix(stream)
> /usr/lib/python2.6/dist-packages/bzrlib/index.py(516)_read_prefix()
-> raise errors.BadIndexFormatSignature(self._name, GraphIndex)
(Pdb)