Software Deployment

hi,
I'm installing DWG Trueview V2 whith installshield script on XP stations, but on some stations, i need to first upgrade windows installer getting to Windows Installer 3.0 version before lunching the DWG.msi file.
Althougth i use the "/norestart" option to install Windowsinstaller, the script always stop and ask for reboot before the DWG Trueview installation.
I read about something like loading and unloading the MSI.DLL to avoid this but don't know how to do that. Thus my MSI logs always return unreference 135???? error code:

=== Verbose logging started: 20/02/2006 18:14:09 Build type: SHIP UNICODE 3.00.3790.2538 Calling process: C:\WINDOWS\System32\msiexec.exe ===
MSI (c) (5C:74) [18:14:09:164]: Resetting cached policy values
MSI (c) (5C:74) [18:14:09:164]: Machine policy value 'Debug' is 0
MSI (c) (5C:74) [18:14:09:164]: ******* RunEngine:
******* Product: W:\_appli en cours de validation\DWG_TRUEVIEW.02000051\Livrables\DWG_TRUEVIEW.02000051\Install\Source\DWGV.msi
******* Action:
******* CommandLine: **********
MSI (c) (5C:74) [18:14:09:164]: Client-side and UI is none or basic: Running entire install on the server.
MSI (c) (5C:74) [18:14:09:164]: Grabbed execution mutex.
MSI (c) (5C:74) [18:14:09:174]: Cloaking enabled.
MSI (c) (5C:74) [18:14:09:174]: Attempting to enable all disabled priveleges before calling Install on Server
MSI (c) (5C:74) [18:14:09:184]: Incrementing counter to disable shutdown. Counter after increment: 0
MSI (c) (5C:74) [18:14:09:234]: Decrementing counter to disable shutdown. If counter >= 0, shutdown will be denied. Counter after decrement: -1
MSI (c) (5C:74) [18:14:09:234]: MainEngineThread is returning 1356289 or 1351169 or 13560897 always a code like 135?????
=== Verbose logging stopped: 20/02/2006 18:14:09 ===

Can anyone help me to uptade and use Windowsinstaller in installshield script whithout rebooting the computer ?