A second example..

ataraxia% bzr branch --no-tree --stacked lp:launchpad                                   /tmp
Created new stacked branch referring to http://bazaar.launchpad.net/~launchpad-pqm/launchpad/db-devel/.
ataraxia% cd launchpad                                                                  /tmp
ataraxia(bzr)% bzr pull --overwrite lp:~launchpad-pqm/launchpad-cscvs/devel/ 
bzr: ERROR: bzrlib.errors.NoSuchRevision: KnitPackRepository('bzr+ssh://bazaar.launchpad.net/~launchpad-pqm/launchpad-cscvs/devel/.bzr/repository/') has no revision ('Arch-1:<email address hidden>%cscvs--devel--1.0--patch-16',)

Traceback (most recent call last):
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/commands.py", line 835, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/commands.py", line 1030, in run_bzr
    ret = run(*run_argv)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/commands.py", line 647, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/builtins.py", line 1016, in run
    branch_from, overwrite, revision_id, local=local)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/branch.py", line 891, in pull
    possible_transports=possible_transports, *args, **kwargs)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/branch.py", line 3154, in pull
    _override_hook_target=_override_hook_target)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/branch.py", line 3031, in pull
    overwrite=overwrite, graph=graph)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/branch.py", line 839, in update_revisions
    overwrite, graph)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/branch.py", line 2974, in update_revisions
    self.target.fetch(self.source, stop_revision)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/branch.py", line 565, in fetch
    pb=pb)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 1544, in fetch
    find_ghosts=find_ghosts, fetch_spec=fetch_spec)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 3735, in fetch
    self._fetch_all_revisions(revision_ids, pb)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 3689, in _fetch_all_revisions
    basis_id = self._fetch_batch(batch, basis_id, cache)
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 3651, in _fetch_batch
    for parent_tree in self.source.revision_trees(parent_ids):
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 2373, in revision_trees
    for inv in inventories:
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 2198, in _iter_inventories
    for text, revision_id in self._iter_inventory_xmls(revision_ids):
  File "/home/dsilvers/dev-bzr/bzr.dev/bzrlib/repository.py", line 2209, in _iter_inventory_xmls
    raise errors.NoSuchRevision(self, record.key)
NoSuchRevision: KnitPackRepository('bzr+ssh://bazaar.launchpad.net/~launchpad-pqm/launchpad-cscvs/devel/.bzr/repository/') has no revision ('Arch-1:<email address hidden>%cscvs--devel--1.0--patch-16',)

bzr 1.18dev on python 2.5.2 (linux2)
arguments: ['/home/dsilvers/bin/bzr', 'pull', '--overwrite', 'lp:~launchpad-pqm/launchpad-cscvs/devel/']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_GB.UTF-8'
plugins:
  bzrtools             /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.17]
  gtk                  /home/dsilvers/.bazaar/plugins/gtk [0.97.0.dev.1]
  launchpad            /home/dsilvers/dev-bzr/bzr.dev/bzrlib/plugins/launchpad [1.18dev]
  multiparent          /home/dsilvers/dev-bzr/bzr.dev/bzrlib/plugins/multiparent.pyc [unknown]
  netrc_credential_store /home/dsilvers/dev-bzr/bzr.dev/bzrlib/plugins/netrc_credential_store [1.18dev]
  pqm                  /usr/lib/python2.5/site-packages/bzrlib/plugins/pqm [1.4dev]
*** 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.
zsh: exit 4     bzr pull --overwrite lp:~launchpad-pqm/launchpad-cscvs/devel/
ataraxia(bzr)%                                                          /tmp/launchpad[8318]