Can't branch on Windows

[Ronald Blaschke]

$ bzr branch git://github.com/rakudo/rakudo.git
bzr: ERROR: [Error 1132] The base address or the file offset specified does not have the proper alignment

bzr.log
...
  File "C:/Documents and Settings/rb/Application Data/bazaar/2.0/plugins\git\fetch.py", line 225, in fetch
    return self.fetch_objects(determine_wants, mapping, pb)
  File "C:/Documents and Settings/rb/Application Data/bazaar/2.0/plugins\git\fetch.py", line 206, in fetch_objects
    target_git_object_retriever, pb)
  File "C:/Documents and Settings/rb/Application Data/bazaar/2.0/plugins\git\fetch.py", line 146, in import_git_objects
    for o in object_iter.iterobjects():
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 869, in iterobjects
    for offset, type, obj in self.data.iterobjects():
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 811, in data
    assert len(self.idx) == len(self._data)
  File "C:/Documents and Settings/rb/Application Data/bazaar/2.0/plugins\git\remote.py", line 125, in idx
    self._data.create_index_v2(self._idx_path, self.resolve_ext_ref)
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 478, in create_index_v2
    entries = self.sorted_entries(resolve_ext_ref)
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 469, in sorted_entries
    ret = list(self.iterentries(resolve_ext_ref))
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 447, in iterentries
    todo = list(self.iterobjects())
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 425, in iterobjects
    map = simple_mmap(f, offset, self._size-offset)
  File "C:\Program Files\Python 2.6\lib\site-packages\dulwich\pack.py", line 100, in simple_mmap
    return mmap.mmap(f.fileno(), size, access=access, offset=offset)
WindowsError: [Error 1132] The base address or the file offset specified does not have the proper alignment