It's not referencing the plugin as too old, it's referencing the Kontakt Player as being too old. I ran into this a couple of weeks ago with Kontakt 7 (not player) because I tried loading a plugin that didn't adhere to the new definitions in one of the newest releases of Kontakt. Installing the current version fixed it.
However, I'm not sure if Kontakt Player gets the same updates as the normal release version of Kontakt. You could touch base with Soundiron and they could tell you if you need to download an older version of the plugin if so.
