switch dialog error in colo workspace

I have colo workspace opened in explorer, trunk revno 466. Click to Switch command on toolbar, the switch dialog appears and suddenly error dialogs pop up:

bzr: ERROR: exceptions.TypeError: argument 2 of QComboBox.addItem() has an invalid type

Traceback (most recent call last):
  File "C:\work\Bazaar\plugins\qbzr\lib\trace.py", line 291, in reports_exception_decorate
  File "C:\work\Bazaar\plugins\explorer\lib\switch_dialog.py", line 64, in initial_load
TypeError: argument 2 of QComboBox.addItem() has an invalid type

bzr 2.1.1 on python 2.5.4 (win32)
arguments: ['bzr', 'explore', '.']
encoding: 'cp1251', fsenc: 'mbcs', lang: 'C'
plugins:
  acad C:\work\Bazaar\plugins\acad [0.8.0]
  bzrtools C:\Program Files\Bazaar\plugins\bzrtools [2.1.0]
  colo C:\work\Bazaar\plugins\colo [0.2.0dev]
  explorer C:\work\Bazaar\plugins\explorer [1.1.0dev]
  fastimport C:\work\Bazaar\plugins\fastimport [0.9.0dev]
  format1 C:\work\Bazaar\plugins\format1 [unknown]
  launchpad C:\Program Files\Bazaar\plugins\launchpad [2.1.1]
  qbzr C:\work\Bazaar\plugins\qbzr [0.19.0dev1]
  rebase C:\Program Files\Bazaar\plugins\rebase [0.5.5]
  scmproj C:\work\Bazaar\plugins\scmproj [0.6.1]
  svn C:\Program Files\Bazaar\plugins\svn [1.0.2]
  x_bit C:\work\Bazaar\plugins\x_bit [1.0.0]

The same with explorer 1.0

qbzr trunk revno 1256.