Bazaar Explorer Crashes on Snow Leopard

Running 'bzr explorer' on my Snow Leopard system causes bzr to crash with the error 'no appropriate 64-bit architecture''. I was able to resolve the problem by forcing python to run in 32-bit mode with

'export VERSIONER_PYTHON_PREFER_32_BIT=yes'

I had both Qt and PyQt installed on my system, both 32-bit only, before I installed bzr. They should have only been installed for for python 2.7, which I installed separately to avoid problems with py2app and 64 bit python.

Here is the output from the explorer command:

$ bzr explorer
bzr: ERROR: exceptions.ImportError: /Library/Frameworks/QtCore.framework/Versions/4/QtCore: no appropriate 64-bit architecture (see "man python" for running in 32-bit mode)

Traceback (most recent call last):
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 911, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 1111, in run_bzr
    ret = run(*run_argv)
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 689, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 704, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/explorer/lib/commands.py", line 144, in run
    from bzrlib.plugins.qbzr.lib import uifactory
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/qbzr/lib/uifactory.py", line 21, in <module>
    from PyQt4 import QtCore, QtGui
ImportError: /Library/Frameworks/QtCore.framework/Versions/4/QtCore: no appropriate 64-bit architecture (see "man python" for running in 32-bit mode)

bzr 2.2.0 on python 2.6.1 (Darwin-10.4.0-i386-64bit)
arguments: ['/usr/local/bin/bzr', 'explorer']
encoding: 'UTF-8', fsenc: 'utf-8', lang: 'en_US.UTF-8'
plugins:
  bash_completion /Library/Python/2.6/site-packages/bzrlib/plugins/bash_completion [2.2.0]
  bzrtools /Library/Python/2.6/site-packages/bzrlib/plugins/bzrtools [2.2.0]
  colo /Library/Python/2.6/site-packages/bzrlib/plugins/colo [0.1.0]
  email /Library/Python/2.6/site-packages/bzrlib/plugins/email [unknown]
  explorer /Library/Python/2.6/site-packages/bzrlib/plugins/explorer [1.1.0dev2]
  extmerge /Library/Python/2.6/site-packages/bzrlib/plugins/extmerge [unknown]
  fastimport /Library/Python/2.6/site-packages/bzrlib/plugins/fastimport [0.9.0dev]
  keychain /Library/Python/2.6/site-packages/bzrlib/plugins/keychain [0.1.0]
  launchpad /Library/Python/2.6/site-packages/bzrlib/plugins/launchpad [2.2.0]
  loom /Library/Python/2.6/site-packages/bzrlib/plugins/loom [2.2.1dev]
  netrc_credential_store /Library/Python/2.6/site-packages/bzrlib/plugins/netrc_credential_store [2.2.0]
  news_merge /Library/Python/2.6/site-packages/bzrlib/plugins/news_merge [2.2.0]
  pipeline /Library/Python/2.6/site-packages/bzrlib/plugins/pipeline [unknown]
  qbzr /Library/Python/2.6/site-packages/bzrlib/plugins/qbzr [0.20.0dev1]
  rewrite /Library/Python/2.6/site-packages/bzrlib/plugins/rewrite [0.6.0]
  svn /Users/sean/.bazaar/plugins/svn [1.0.4]
  upload /Library/Python/2.6/site-packages/bzrlib/plugins/upload [1.0.0dev]
  xmloutput /Library/Python/2.6/site-packages/bzrlib/plugins/xmloutput [0.8.6]

*** 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.