I've been struggling with this too, but I think I've cracked it, thanks to the clues in the last post about the order of installation, with this scripteroo:
@echo off
cls
echo Set variables
set source=\\server\share\applications\quicktime
set log=%temp%\QuickTimeInstall.log
echo %date% %time% %~nx0 : Start install script>%log%
:FindSource
echo %date% %time% %~nx0 : Find Source Folder
if /i exist %source% goto FindExe
echo %date% %time% %~nx0 : %source% folder not found. Quitting>>%log%
goto eof
:FindExe
echo %date% %time% %~nx0 : Find executable
if /i exist %source%\QuickTimeInstaller.exe goto Main
echo %date% %time% %~nx0 : %source%\QuickTimeInstaller.exe file not found (permissions?). Quitting>>%log%
goto eof
:Main
echo %date% %time% %~nx0 : Make directory %temp%\QuickTime
echo %date% %time% %~nx0 : Make directory %temp%\QuickTime>>%log%
if /i not exist %temp%\QuickTime md %temp%\QuickTime
echo %date% %time% %~nx0 : Copy %source%\QuickTimeInstaller.exe to %temp%>>%log%
echo %date% %time% %~nx0 : Copy %source%\QuickTimeInstaller.exe to %temp%
copy %source%\QuickTimeInstaller.exe %temp%\QuickTime>nul
echo %date% %time% %~nx0 : CD to %temp%\QuickTime>>%log%
echo %date% %time% %~nx0 : CD to %temp%\QuickTime
c:
cd %temp%\QuickTime
echo %date% %time% %~nx0 : Extract QuickTime MSI files>>%log%
echo %date% %time% %~nx0 : Extract QuickTime MSI files
QuickTimeInstaller /extract
echo %date% %time% %~nx0 : Run %temp%\AppleApplicationSupport.msi>>%log%
echo %date% %time% %~nx0 : Run %temp%\AppleApplicationSupport.msi
AppleApplicationSupport.msi /quiet /norestart /l %log%.tmp
echo %date% %time% %~nx0 : Copy temp log to main log file.
type %log%.tmp >>%log%
echo %date% %time% %~nx0 : Run %temp%\AppleSoftwareUpdate.msi>>%log%
echo %date% %time% %~nx0 : Run %temp%\AppleSoftwareUpdate.msi
AppleSoftwareUpdate.msi /quiet /norestart /l %log%.tmp
echo %date% %time% %~nx0 : Copy temp log to main log file.
type %log%.tmp >>%log%
echo %date% %time% %~nx0 : Run %temp%\QuickTime.msi>>%log%
echo %date% %time% %~nx0 : Run %temp%\QuickTime.msi
QuickTime.msi /quiet /norestart /l %log%.tmp
echo %date% %time% %~nx0 : Complete log file.
type %log%.tmp >>%log%
:eof
Just save this as a .bat (or.cmd) file, and call it from your (Computer Configuration) GPO. Although note that I've not tested it from a GPO, only as a double-click and as a Task Sequence step in SCCM. Of course the QuickTimeInstaller.exe needs to be present in the \\server\share\applications\quicktime path!
Thinking about it, you'll only want this script to run once (not on EVERY reboot!) so, add echo Done!>%SystemDrive%\QuicktimeInstalled.flg just before :eof and if /i exist %SystemDrive%\QuicktimeInstalled.flg goto eof somewhere at the top of the script (e.g. line 2). So, when the script gets to the end it'll create the .flg file, then on subsequent runs, if/when it finds this .flg file. the script will just quit out.
The usual "The script is supplied "as is" and you run it at your own risk" caveat applies.