the NAL object is set to run as a secure user so should have rights

I am installing XPSP2 (after three years I know) but to quite a large
number of machines. This needs to be automated and WOL will wake the
machines up at 4am and install XPSP2 via a script. A NAL object will run
the script and the object will be associated to the machine, hence when
the WOL kickes in, scheduler will run the associated NAL objects.

This is the script i am running

@echo off
Title XPSP2 Install
if exist c:\Windows\Options\Flags\INS-XPSP2.txt goto done
echo.
echo.
echo Please wait for XP Service Pack 2 to install
echo.
echo.
echo.Once XP Service Pack 2 has installed the computer will reboot
automatically
echo.
echo.
echo.
C:\Windows\Options\XPSP2\xpsp2.exe /passive /norestart /n /f
regedit /s C:\Windows\Options\XPSP2\xpsp2.reg
echo. > c:\Windows\Options\Flags\INS-XPSP2.txt
c:\windows\system32\shutdown -s -t 15
:done

When I take out the XPSP.exe command line the object reboots so XPSP2.exe
must be sotpping the NLA object from rebooting?

I think i may have a (naff) workaround but this is really screwing me