I can still reproduce this bug using the same sequence as Nicholas Allen. I can't reproduce bug 395556, so they don't seem to be related.

Bazaar (bzr) 2.2.5dev
  from bzr checkout C:/Users/me/Sources/bzr/bzr.2.2
    revision: 5134
    revid: <email address hidden>
    branch nick: bzr.2.2
  Python interpreter: C:\Users\me\Sources\bzr\myenv\Scripts\python.exe 2.6.6
  Python standard library: C:\Users\me\Sources\bzr\myenv\lib
  Platform: Windows-7-6.1.7601-SP1
  bzrlib: C:\Users\me\Sources\bzr\bzr.2.2\bzrlib
  Bazaar configuration: C:\Users\me\AppData\Roaming\bazaar\2.0
  Bazaar log file: C:\Users\me\Documents\.bzr.log



Tue 2011-07-12 16:03:51 +0200
0.118  bazaar version: 2.2.5dev
0.118  bzr arguments: [u'mv', u'dir/test.txt', u'dir2/test2.txt']
0.130  looking for plugins in C:/Users/me/AppData/Roaming/bazaar/2.0/plugins
0.190  looking for plugins in C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\plugins
0.216  encoding stdout as sys.stdout encoding 'cp850'
0.227  failed to load compiled extension: No module named _static_tuple_c
0.232  failed to load compiled extension: No module named _rio_pyx
0.237  failed to load compiled extension: No module named _dirstate_helpers_pyx
0.252  failed to load compiled extension: cannot import name _btree_serializer_pyx
0.260  failed to load compiled extension: No module named _chk_map_pyx
0.262  failed to load compiled extension: No module named _bencode_pyx
0.286  failed to load compiled extension: No module named _annotator_pyx
0.287  failed to load compiled extension: No module named _knit_load_data_pyx
0.293  failed to load compiled extension: No module named _known_graph_pyx
0.295  failed to load compiled extension: No module named _groupcompress_pyx
0.300  opening working tree 'C:/Users/me/Sources/bzr-bug'
0.318  attempting to move dir/test.txt => dir2/test2.txt
0.337  Traceback (most recent call last):
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\commands.py", line 912, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\commands.py", line 1112, in run_bzr
    ret = run(*run_argv)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\commands.py", line 690, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\commands.py", line 705, in run
    return self._operation.run_simple(*args, **kwargs)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\builtins.py", line 837, in run
    self._run(tree, names_list, rel_names, after)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\builtins.py", line 926, in _run
    tree.rename_one(src, dest, after=after)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\workingtree_4.py", line 1257, in rename_one
    WorkingTree.rename_one(self, from_rel, to_rel, after)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\workingtree.py", line 1516, in rename_one
    inv.add(from_entry)
  File "C:\Users\me\Sources\bzr\bzr.2.2\bzrlib\inventory.py", line 1289, in add
    self._byid[entry.file_id])
DuplicateFileId: File id {test.txt-20110712140117-52xz1fbsaz36moix-1} already exists in inventory as InventoryFile('test.txt-20110712140117-52xz1fbsaz36moix-1', u'test.txt', parent_id='dir-20110712140103-nt0epm8bv54p9kou-1', sha1=None, len=None, revision=None)