I think I’ve figured out why my autoinstallers for 3DS Max 9 and Maya 2008 didn’t work – they required the directx redistributable package to run, specifically d3dx9_34.dll for Maya and some earlier version for 3DS Max. In addition to the isscript autoIt install (required because the installshield msi file will break all other versions of isscript.msi if installed via group policy), a directx silent install will be required to ensure the installation can roll out on lab machines.