qcommit/qrevert/qadd: after refresh: list indices must be integers

I had qcommit open, added some folders and files to the working tree and then clicked Refresh in qcommit, whereupon the following error occurred:

bzr: ERROR: exceptions.TypeError: list indices must be integers

Traceback (most recent call last):
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\trace.py", line 291, in reports_exception_decorate
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\commit.py", line 470, in load
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\treewidget.py", line 1466, in refresh
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\treewidget.py", line 512, in set_tree
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\treewidget.py", line 612, in process_inventory
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\treewidget.py", line 1050, in refs2indexes
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\treewidget.py", line 1044, in ref2index
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\treewidget.py", line 694, in _index_from_id
TypeError: list indices must be integers

bzr 2.1.0rc1 on python 2.5.4 (win32)
arguments: ['C:\\Program Files (x86)\\Bazaar\\bzr.exe', '--command=commit', '--dir=C:\\WoW\\Interface\\AddOns\\DeadHorse']
encoding: 'cp1252', fsenc: 'mbcs', lang: None
plugins:
  bzrtools C:\Program Files (x86)\Bazaar\plugins\bzrtools [2.1.0b1]
  colo C:\Users\Owner\AppData\Roaming\bazaar\2.0\plugins\colo [0.0.2dev]
  explorer C:\Program Files (x86)\Bazaar\plugins\explorer [0.11.0]
  extmerge C:\Program Files (x86)\Bazaar\plugins\extmerge [unknown]
  launchpad C:\Program Files (x86)\Bazaar\plugins\launchpad [2.1.0rc1]
  netrc_credential_store C:\Program Files (x86)\Bazaar\plugins\netrc_credential_store [2.1.0rc1]
  qbzr C:\Program Files (x86)\Bazaar\plugins\qbzr [0.18.0]
  rebase C:\Program Files (x86)\Bazaar\plugins\rebase [0.5.5]
  svn C:\Program Files (x86)\Bazaar\plugins\svn [1.0.1]
  upload C:\Program Files (x86)\Bazaar\plugins\upload [1.0.0dev]
  xmloutput C:\Program Files (x86)\Bazaar\plugins\xmloutput [0.8.5]