I was getting an error like this:

/etc/cron.daily/etckeeper:
bzr: ERROR: exceptions.UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 34: ordinal not in range(128)

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 853, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1055, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 661, in run_argv_aliases
    return self.run_direct(**all_cmd_args)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 665, in run_direct
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 122, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 156, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 659, in run
    no_recurse, action=action, save=not dry_run)
  File "/usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py", line 521, in smart_add
    for subf in sorted(os.listdir(abspath)):
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 34: ordinal not in range(128)

bzr 2.1.4 on python 2.6.5 (Linux-2.6.35.4-rscloud-x86_64-with-Ubuntu-10.04-lucid)
arguments: ['/usr/bin/bzr', 'add', '-q', '.']
encoding: 'ANSI_X3.4-1968', fsenc: 'ANSI_X3.4-1968', lang: None
plugins:
  bzrtools             /usr/lib/python2.6/dist-packages/bzrlib/plugins/bzrtools [2.1.0]
  etckeeper            /usr/lib/python2.6/dist-packages/bzrlib/plugins/etckeeper [unknown]
  launchpad            /usr/lib/python2.6/dist-packages/bzrlib/plugins/launchpad [2.1.4]
  netrc_credential_store /usr/lib/python2.6/dist-packages/bzrlib/plugins/netrc_credential_store [2.1.4]
  news_merge           /usr/lib/python2.6/dist-packages/bzrlib/plugins/news_merge [2.1.4]

*** 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.
etckeeper warning: bzr add failed
Committing to: /etc/
modified apache2/passwd.htdigest
modified apache2/sites-available/svn.jj5.net-ssl
Committed revision 87.

I’ve tried to fix it by adding:

export LANG=en_AU.UTF-8
export LANGUAGE=en_AU:en

As lines 2 and 3 in /etc/cron.daily/etckeeper.

Now I’ll wait a day or two and see if it worked…