How do I delete a git submodule?

Hi!

I am trying to remove a submodule from a project, but can't figure out how to do it. With "modules/aldc" as a submodule:

  $ cat .gitmodules
  [submodule "modules/aldc"]
          path = modules/aldc
          url = [...cut...]
  [...more entries here...]
  $ git status
  [...cut...]
  nothing to commit (working directory clean)

Starting from a clean set-up.

  $ git submodule rm modules/aldc
  -ff17d9e0e76d01e99d26aa16b28cf327c5abb48a modules/aldc
  $ git status
  [...cut...]
  nothing to commit (working directory clean)

The obvious command didn't give any errors, but didn't do anything, either. (I notice that there is no mention of a "git submodule rm" on the git-submodule man page.)

  $ git rm modules/aldc
  rm 'modules/aldc'
  fatal: git rm: modules/aldc: Permission denied
  $ git status
  [...cut...]
  nothing to commit (working directory clean)

Nope, that didn't work either.

What am I missing?

  $ git --version
  git version 1.6.0.2.1172.ga5ed0

(This is Git-1.6.0.2-preview20080923 on Windows XP)