Comment 2 for bug 614235

I'm getting the same thing specifically when trying to run qdiff dialog.

bzr: ERROR: exceptions.IndexError: pop from empty list

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/qbzr/lib/trace.py", line 300, in reports_exception_decorate
    return f(*args, **kargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/qbzr/lib/diffwindow.py", line 235, in initial_load
    op.run()
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 118, in run
    self.cleanups, self.func, self, *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/plugins/qbzr/lib/diffwindow.py", line 248, in _initial_load
    self.load_diff()
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/qbzr/lib/diffwindow.py", line 404, in load_diff
    data, properties_changed)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/qbzr/lib/diffview.py", line 435, in append_diff
    insertIxsWithChangesHighlighted(ixs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/qbzr/lib/diffview.py", line 384, in insertIxsWithChangesHighlighted
    tag, n = g.pop(0)
IndexError: pop from empty list

bzr 2.1.1 on python 2.6.2 (linux2)
arguments: ['/usr/bin/bzr', 'qlog']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  bzrtools /usr/lib/python2.6/dist-packages/bzrlib/plugins/bzrtools [2.1.0]
  launchpad /usr/lib/python2.6/dist-packages/bzrlib/plugins/launchpad [2.1.1]
  netrc_credential_store /usr/lib/python2.6/dist-packages/bzrlib/plugins/netrc_credential_store [2.1.1]
  news_merge /usr/lib/python2.6/dist-packages/bzrlib/plugins/news_merge [2.1.1]
  qbzr /usr/lib/python2.6/dist-packages/bzrlib/plugins/qbzr [0.19.0]

The commit in question went particularly nasty it picked up a lot of duplicate data along with the changes. Maybe it was a problem with the commit itself. *note the diffing does work in loggerhead.
http://bazaar.launchpad.net/~inklink28/mfaf/trunk/revision/123

I run two different machines here's their version data
Bazaar (bzr) 2.1.1
  Python interpreter: /usr/bin/python 2.6.5
  Python standard library: /usr/lib/python2.6
  Platform: Linux-2.6.32-21-generic-i686-with-Ubuntu-10.04-lucid
  bzrlib: /usr/lib/python2.6/dist-packages/bzrlib
  Bazaar configuration: /home/ubuntu/.bazaar
  Bazaar log file: /home/ubuntu/.bzr.log

Bazaar (bzr) 2.1.1
  Python interpreter: /usr/bin/python 2.6.2
  Python standard library: /usr/lib/python2.6
  Platform: Linux-2.6.28-19-generic-i686-with-Ubuntu-9.04-jaunty
  bzrlib: /usr/lib/python2.6/dist-packages/bzrlib
  Bazaar configuration: /home/james/.bazaar
  Bazaar log file: /home/james/.bzr.log