Bzr crashes on merge

When merging two branches bzr cashed. This seems related to bzr-search. Here is the error meesage:

bzr: failed to report crash using apport:
     OSError(13, 'Permission denied')
bzr: ERROR: exceptions.Exception: md5 collision! rad! b06f08f74f259631d196c99f2e119150

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 912, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1112, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 690, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 705, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 3200, in run
    exclude=safe_relpath_files(tree, exclude))
  File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 194, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree_4.py", line 197, in commit
    result = WorkingTree3.commit(self, message, revprops, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 194, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py", line 201, in commit
    *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commit.py", line 286, in commit
    possible_master_transports=possible_master_transports)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 131, in run
    self.cleanups, self.func, self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commit.py", line 451, in _commit
    self.branch.set_last_revision_info(new_revno, self.rev_id)
  File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 194, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/branch.py", line 2827, in set_last_revision_info
    self._run_post_change_branch_tip_hooks(old_revno, old_revid)
  File "/usr/lib/python2.6/dist-packages/bzrlib/branch.py", line 1201, in _run_post_change_branch_tip_hooks
    hook(params)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/search/__init__.py", line 59, in auto_index_branch
    search_index.index_branch(result.branch, result.new_revid)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py", line 321, in index_branch
    self.index_revisions(branch, revs_to_index)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py", line 336, in index_revisions
    outer_bar)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py", line 384, in _index_revisions
    self._add_index(builder)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/search/index.py", line 399, in _add_index
    raise Exception("md5 collision! rad! %s" % index_name)
Exception: md5 collision! rad! b06f08f74f259631d196c99f2e119150

bzr 2.2.1 on python 2.6.6 (Linux-2.6.35-28-generic-pae-i686-with-Ubuntu-10.10-maverick)
arguments: ['/usr/bin/bzr', 'commit']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.utf8'
plugins:
  bash_completion /usr/lib/python2.6/dist-packages/bzrlib/plugins/bash_completion [2.2.1]
  bzrtools /usr/lib/python2.6/dist-packages/bzrlib/plugins/bzrtools [2.2.0]
  launchpad /usr/lib/python2.6/dist-packages/bzrlib/plugins/launchpad [2.2.1]
  netrc_credential_store /usr/lib/python2.6/dist-packages/bzrlib/plugins/netrc_credential_store [2.2.1]
  news_merge /usr/lib/python2.6/dist-packages/bzrlib/plugins/news_merge [2.2.1]
  search /usr/lib/python2.6/dist-packages/bzrlib/plugins/search [1.7.0dev]