Bazaar Won't Commit or Update

[A. S. Budden]

Dear all,

One of my colleagues is having some fairly major problems with Bazaar.
 He has made some changes to the files in his working directory and
now cannot commit (or even update).  This seems to have affected the
(bzr-externals) library modules in the project as well.  We use
heavyweight checkouts on all of our projects here (in case it makes a
difference).

The output of "bzr update":

     bzr: ERROR: [Errno 2] No such file or directory

Similar output comes from "bzr ci -m Message" or "bzr pull
f:/path/to/repository/branch".  Adding the "--verbose" option or the
"--no-plugins" option makes no difference.

I'm a bit lost as to what to do with this: it doesn't tell me which
file or directory is missing!  This is a little scary as it's the
first fairly fundamental problem we've had with Bazaar...

Any help anyone could offer in getting this working again (or at least
working out why it isn't working) would be greatly appreciated.

Al

Some more information in case it's helpful:

Output of "bzr version" (excluding the copyright notice etc):

  Bazaar (bzr) 2.4.0
  Python interpreter: C:\Program Files (x86)\Bazaar\python26.dll 2.6.6
  Python standard library: C:\Program Files (x86)\Bazaar\lib\library.zip
  Platform: Windows-7-6.1.7601-SP1
  bzrlib: C:\Program Files (x86)\Bazaar\lib\library.zip\bzrlib
  Bazaar configuration: C:\Users\Kevin Vans-Colina\AppData\Roaming\bazaar\2.0
  Bazaar log file: C:\Users\Kevin Vans-Colina\Documents\.bzr.log

Output of "bzr check" (in one of the bzr-externals library module directories):

    Checking working tree at 'C:/CSV Code/WorkDir/LibraryModules/CMSIS'.
    Checking branch at 'file:///C:/CSV%20Code/WorkDir/LibraryModules/CMSIS/'.
    Checking repository at
'file:///C:/CSV%20Code/WorkDir/LibraryModules/CMSIS/'.
    checked repository
file:///C:/CSV%20Code/WorkDir/LibraryModules/CMSIS/ format
RepositoryFormat2a()
        46 revisions
        26 file-ids
    checked branch file:///C:/CSV%20Code/WorkDir/LibraryModules/CMSIS/
format Branch format 7

Output of "bzr info":

    Checkout (format: 2a)
    Location:
           checkout root: .
      checkout of branch: F:/VCS/LibraryModules/CMSIS_STM32/trunk

    Related branches:
      parent branch: F:/VCS/LibraryModules/CMSIS_STM32/trunk