My only experience with Error Code 7 was that it was related to currently running applications. I received this error so tried running the installer in interactive mode. It asked me to close Outlook, Word, IE and Messenger. I did that, terminated the installer and ran the silent install script again and it worked. Obviously, this shouldn't happen when using RunOnceEx or similar. I was trying a "shortcut" to install the collection on a machine after it had been built.