git-merge-changelog usage error during rebase

[James Youngman]

$ git checkout jy/auto-gettext
Switched to branch "jy/auto-gettext"
$ git rebase master
First, rewinding head to replay your work on top of it...
Applying Update to version 0.17 of GNU gettext.
error: patch failed: ChangeLog:41
error: ChangeLog: patch does not apply
Using index info to reconstruct a base tree...
Falling back to patching base and 3-way merge...
/usr/local/bin/git-merge-changelog: expected three arguments
Auto-merged .gitignore
Removed ABOUT-NLS
Auto-merged ChangeLog
CONFLICT (content): Merge conflict in ChangeLog
Auto-merged import-gnulib.sh
Removed po/Makefile.in.in
Failed to merge in the changes.
Patch failed at 0001.

When you have resolved this problem run "git rebase --continue".
If you would prefer to skip this patch, instead run "git rebase --skip".
To restore the original branch and stop rebasing run "git rebase --abort".

The ChangeLog file doesn't have any conflict markers in it; in fact it
seems to be the version from master.

$ cat .git/config
[core]
        repositoryformatversion = 0
        filemode = true
        bare = false
        logallrefupdates = true
[remote "origin"]
        url = ssh://address@hidden/srv/git/findutils.git
        fetch = +refs/heads/*:refs/remotes/origin/*
[branch "master"]
        remote = origin
        merge = refs/heads/master
[format]
        headers = "To: address@hidden"
[branch "rel-4-4-fixes"]
        remote = origin
        merge = refs/heads/rel-4-4-fixes
[branch "rel-4-3-fixes"]
        remote = origin
        merge = refs/heads/rel-4-3-fixes
[branch "rel-4-2-fixes"]
        remote = origin
        merge = refs/heads/rel-4-2-fixes
[merge "cl-merge"]
        name = GNU-style ChangeLog merge driver
        driver = /usr/local/bin/git-merge-changelog
$ cat .gitattributes
ChangeLog    merge=cl-merge
$  /usr/local/bin/git-merge-changelog --version
/usr/local/bin/git-merge-changelog
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Written by Bruno Haible.
$ git --version
git version 1.5.6.5


Any ideas?

James.