Trivial startup script won't run in Vista

I have a very simple Startup script run by a GPO that I've used in Win XP
for a long time without any problems. It needed a slight modification for
Vista.

The Vista portion of the script runs OK interactively with a standard user
account or an admin account, but does NOT run as a Startup script. I've also
tried it as a Logon script, where it also fails. Here is the script--

-----------------------
VER | FIND "Version 5."
IF %ERRORLEVEL%==1 GOTO VistaOrHigher
XCOPY /o /h /s /y "%0\..\5XFiles" "%ALLUSERSPROFILE%\Desktop\"
ATTRIB +R "%ALLUSERSPROFILE%\Desktop\Shared Documents"
GOTO End

:VistaOrHigher
XCOPY /o /h /s /y "%0\..\6XFiles" "%Public%\Desktop\"
ATTRIB +R "%Public%\Desktop\Shared Documents"
:End
-----------------------

Using RSOP, I've verified that the GPO is being processed by the computers.
ACLs on the destination folder are default, as set by Windows Setup. There
are no errors for this GPO in the Windows logs.

I've modified the XCOPY line to redirect XCOPY output to a file in %TEMP%;
the log file is not created when run by GPO. It is created (and contains no
surprises) when run interactively. So it appears that the script, or at
least that line in the script, is not running when executed by GPO.

Any idea why this is failing?

--
Jeff Vandervoort
JRVsystems
http://www.jrvsystems.com