Crash when adding new pipe to the front

$ bzr pipes
* edit-commit-msg-link
$ bzr add-pipe --before fix-stripped-text
bzr: ERROR: bzrlib.errors.ObjectNotLocked: <bzrlib.groupcompress._GCGraphIndex object at 0x1a9bc90> is not locked

*** 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
    attaching the crash file
        /home/tim/.cache/crash/bzr-20091123033251-4734.crash
    and including a description of the problem.

    The crash file is plain text and you can inspect or edit it to remove
    private information.