For the package we use in our environment, we did not extract the MSI or the MSP. We run Silverlight.2.0.exe /q /ignorewarnings /noupdate
The command line argument /ignorewarnings will make sure that there will be no no-fatal error codes returned.
The command line argument /noupdate will disable the need to add a registry entry to disable the auto-update feature.
Previous to having the /noupdate command line argument our solution was to use an installation wrapper to add the registry entries as documented in this thread. These command lines were provided by a very reliable source.
/doNotRequireDRMPrompt = turns off the 1st use prompt allowing DRM Playback without requiring any end-user intervention. This setting is automatically included when the quiet install switch is used. By default, DRM Playback is set to prompt on 1st use.
/qu = quiet uninstall. This uninstalls Silverlight without seeing the GUI. Note: This will only uninstall the exact same version that it installed, so is typically only useful for testing scenarios.
Note: The /doNotRequireDRMPrompt and /ignorewarnings switches are only available with the version of Silverlight 2 GDR 2 (KB 960353 / 2.0.40115.0) or later.