Hi,
the Sound Installer for DVD Revision is not an update for the plugin or library, it is for when you need to install the Sound Library from DVD onto an OS that is newer than the DVD Print and the installer on disc is incompatible with the OS.
The second message means you have installed the limited web install of the Sound Library and are trying to apply the Library update, which only works on the Library installed from DVD.
So you should uninstall the limited web content and install the Library from DVD, then run the Library update.