Push to repository: "Operation not permitted"

[Ben Finney]

Howdy all,

I'm trying to push a branch to a repository on a USB stick, but
getting an error that appears to be ultimately from the filesystem.

=====
$ bzr version
Bazaar (bzr) 1.5
  Python interpreter: /usr/bin/python 2.5.2
  Python standard library: /usr/lib/python2.5
  bzrlib: /usr/lib/python2.5/site-packages/bzrlib
  Bazaar configuration: /home/bignose/.bazaar
  Bazaar log file: /home/bignose/.bzr.log
[...]

$ bzr init-repository --trees /media/sdb1/bazaar/
$ bzr info /media/sdb1/bazaar/
Shared repository with trees (format: pack-0.92)
Location:
  shared repository: /media/sdb1/bazaar

$ bzr init /media/sdb1/bazaar/roaming-profile/
$ bzr info /media/sdb1/bazaar/roaming-profile/
Repository tree (format: pack-0.92)
Location:
  shared repository: /media/sdb1/bazaar
  repository branch: /media/sdb1/bazaar/roaming-profile

$ bzr info .
Standalone tree (format: pack-0.92)
Location:
  branch root: .
[...]

$ bzr push /media/sdb1/bazaar/roaming-profile/
bzr: ERROR: [Errno 1] Operation not permitted
$ bzr push --verbose /media/sdb1/bazaar/roaming-profile/
bzr: ERROR: [Errno 1] Operation not permitted
=====

What can I do to find out what Bazaar is trying to do that fails here?
What can I do to fix it?

-- 
 \              “Dvorak users of the world flgkd!” —Kirsten Chevalier, |
  `\                                                rec.humor.oracle.d |
_o__)                                                                  |
Ben Finney