I just got this error when attempting to merge from another local branch:

$ bzr merge ../trunk-bzr-svn
bzr: ERROR: bzrlib.errors.BzrCheckError: Internal check failed: Cannot add revision(s) to repository: missing chk node(s) for id_to_entry maps                                                                                              

Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/bzrlib/commands.py", line 927, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/bzrlib/commands.py", line 1127, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib64/python2.7/site-packages/bzrlib/commands.py", line 692, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib64/python2.7/site-packages/bzrlib/commands.py", line 714, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/bzrlib/builtins.py", line 3941, in run
    location, revision, remember, possible_transports, None)
  File "/usr/lib64/python2.7/site-packages/bzrlib/builtins.py", line 4074, in _get_merger_from_branch
    other_revision_id, base_revision_id, other_branch, base_branch)
  File "/usr/lib64/python2.7/site-packages/bzrlib/merge.py", line 410, in from_revision_ids
    merger.set_other_revision(other, other_branch)
  File "/usr/lib64/python2.7/site-packages/bzrlib/merge.py", line 551, in set_other_revision
    self._maybe_fetch(other_branch, self.this_branch, self.other_rev_id)
  File "/usr/lib64/python2.7/site-packages/bzrlib/merge.py", line 568, in _maybe_fetch
    target.fetch(source, revision_id)
  File "/usr/lib64/python2.7/site-packages/bzrlib/decorators.py", line 194, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/bzrlib/branch.py", line 687, in fetch
    pb=pb)
  File "/usr/lib64/python2.7/site-packages/bzrlib/repository.py", line 1781, in fetch
    find_ghosts=find_ghosts, fetch_spec=fetch_spec)
  File "/usr/lib64/python2.7/site-packages/bzrlib/decorators.py", line 194, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/bzrlib/repository.py", line 3437, in fetch
    find_ghosts=find_ghosts)
  File "/usr/lib64/python2.7/site-packages/bzrlib/fetch.py", line 73, in __init__
    self.__fetch()
  File "/usr/lib64/python2.7/site-packages/bzrlib/fetch.py", line 99, in __fetch
    self._fetch_everything_for_search(search)
  File "/usr/lib64/python2.7/site-packages/bzrlib/fetch.py", line 127, in _fetch_everything_for_search
    stream, from_format, [])
  File "/usr/lib64/python2.7/site-packages/bzrlib/repository.py", line 4105, in insert_stream
    hint = self.target_repo.commit_write_group()
  File "/usr/lib64/python2.7/site-packages/bzrlib/repository.py", line 1640, in commit_write_group
    result = self._commit_write_group()
  File "/usr/lib64/python2.7/site-packages/bzrlib/repofmt/pack_repo.py", line 2333, in _commit_write_group
    hint = self._pack_collection._commit_write_group()
  File "/usr/lib64/python2.7/site-packages/bzrlib/repofmt/pack_repo.py", line 2171, in _commit_write_group
    "Cannot add revision(s) to repository: " + problems_summary)
BzrCheckError: Internal check failed: Cannot add revision(s) to repository: missing chk node(s) for id_to_entry maps

bzr 2.3.4 on python 2.7.1 (Linux-2.6.40.4-5.fc15.x86_64-x86_64-with-
    fedora-15-Lovelock)
arguments: ['/usr/bin/bzr', 'merge', '../trunk-bzr-svn']
plugins: bash_completion[2.3.4], extmerge[unknown], launchpad[2.3.4],
    netrc_credential_store[2.3.4], news_merge[2.3.4], qbzr[0.20.1],
    svn[1.1.1dev]
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'

*** Bazaar has encountered an internal error.  This probably indicates a
    bug in Bazaar.  You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem