This was even more annoying than most failed software installs as I've not had a problem with installing SCORCH in the past, but this time it failed almost straight away.
Each time I went through the install, changing various options as I went, even rebuilding the OS from scratch in case a windows update was messing it about, I hit the same error.
MSI (s) (90:90) [07:22:09:721]: MainEngineThread is returning 1639
Info 1639.Invalid command line argument. Consult the Windows Installer SDK for detailed command line help.
It took me a while to cotton on as to what was causing this, but just to save someone else the time, watch out for complex passwords, you can't have a password that contains a " in it otherwise it will cause this problem as it passes the password along to the silent install string for the MSI which interprets it as the begining of a quote wrapper in the command line.
So if I add the " into the command line, this is what the SCO ManagementServiceMSI was trying to run:
Command Line: REPORTINGLEVEL=2 MYUSERNAME=TRUSTLAB\SCORCHSA MYPASSWORD=******"*** INSTALLDIR=C:\Program Files (x86)\Microsoft System Center 2012\Orchestrator REBOOT=ReallySuppress CURRENTDIRECTORY=C:\Users\SCORCHAdmin\AppData\Local\Microsoft System Center 2012\Orchestrator CLIENTUILEVEL=3 MSICLIENTUSESEXTERNALUI=1 CLIENTPROCESSID=3068