UTF-8 error blocking import of Mercurial (hg) repository

I have a Mercurial repository that exported successfully to the fast-import format. However, when I try to import, it fails with a 'utf8' error:

...
16:02:09 800/2100 commits processed at 199/minute (800)
16:03:52 900/2100 commits processed at 157/minute (900)
ABORT: exception occurred processing commit :901
bzr: ERROR: exceptions.UnicodeDecodeError: 'utf8' codec can't decode byte 0xb9 in position 14: unexpected code byte

Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/bzrlib/commands.py", line 946, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/pymodules/python2.6/bzrlib/commands.py", line 1150, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/pymodules/python2.6/bzrlib/commands.py", line 699, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/pymodules/python2.6/bzrlib/commands.py", line 721, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/pymodules/python2.6/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/pymodules/python2.6/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/pymodules/python2.6/bzrlib/plugins/fastimport/cmds.py", line 314, in run
    user_map=user_map)
  File "/usr/lib/pymodules/python2.6/bzrlib/plugins/fastimport/cmds.py", line 40, in _run
    return proc.process(p.iter_commands)
  File "/usr/lib/pymodules/python2.6/bzrlib/plugins/fastimport/processors/generic_processor.py", line 311, in process
    super(GenericProcessor, self)._process(command_iter)
  File "/usr/lib/pymodules/python2.6/fastimport/processor.py", line 76, in _process
    handler(self, cmd)
  File "/usr/lib/pymodules/python2.6/bzrlib/plugins/fastimport/processors/generic_processor.py", line 536, in commit_handler
    handler.process()
  File "/usr/lib/pymodules/python2.6/fastimport/processor.py", line 158, in process
    handler(self, fc)
  File "/usr/lib/pymodules/python2.6/bzrlib/plugins/fastimport/bzr_commit_handler.py", line 890, in modify_handler
    self._modify_item(filecmd.path.decode('utf8'), kind,
  File "/usr/lib/python2.6/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xb9 in position 14: unexpected code byte

I'm running this on Ubuntu. bzr version "2.4.0-1~bazaar1~lucid1", and bzr-fastimport version "0.11.0-1~lucid1".

Maybe this problem is because older Mercurial commits didn't always contain valid UTF-8 data??

Note: I was able to work around this issue by changing
"path.decode('utf-8')" to instead say: "path.decode('utf-8', 'replace')"
on lines 890 and 895 of /usr/lib/pymodules/python2.6/bzrlib/plugins/fastimport/bzr_commit_handler.py