git-p4 under cygwin

I'm trying to use git-p4 to push changes from git into a Perforce repository under Cygwin, using the cygwin git installation. I followed the instructions at http://kb.perforce.com/article/1417/git-p4 and everything works fine until I do the final 'git p4 submit'.

During the submit command I get the following error:
 
Path '/cygdrive/c/work/perforce/config_test\...' is not under client's root 'c:\work\perforce\config_test'.
Traceback (most recent call last):
  File "/usr/local/bin/git-p4", line 2371, in <module>
    main()
  File "/usr/local/bin/git-p4", line 2366, in main
    if not cmd.run(args):
  File "/usr/local/bin/git-p4", line 1130, in run
    p4_sync("...")
  File "/usr/local/bin/git-p4", line 137, in p4_sync
    p4_system(["sync", path])
  File "/usr/local/bin/git-p4", line 131, in p4_system
    subprocess.check_call(real_cmd, shell=expand)
  File "/usr/lib/python2.6/subprocess.py", line 498, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['p4', 'sync', '...']' returned non-zero exit status 1

Is there are recommended approach for using git-p4 on Windows? I also tried using the non-Cygwin installations of git, but these don't seem to have any Python support in them, so the git-p4 code won't run at all.

Many thanks in advance

Paul Chown