Hmm... Could you give me a bit of history on your computer? I want to mainly know if you have Windows 98 up to date, what video drivers you are using, and if possible what motherboard your computer has.
That error doesnt mean that the plugin is missing but that certain parts it depends on could be missing. Not having DirectX 8.0 (or higher) would cause this error for example. Not having certain other things would also pop up the error... I will research a bit more on this and get back to you later.