InstallPackage
(string) If InstallType is set to INSTALLTYPE_NETWORK_IMAGE, this parameter should be the full path to the product that is to be patched. To make the installer apply the patch to every eligible product listed in the patch package, set this parameter to an empty string ("") and InstallType to INSTALLTYPE_DEFAULT.
If InstallType is set to INSTALLTYPE_SINGLE_INSTANCE, the installer applies the patch to the product specified by this parameter. In this case, other eligible products listed in the patch package are ignored and the this parameter should contain the a string representing the product code of the instance to patch. This type of installation requires the installer running Windows Server 2003 or Windows XP.