Subterranea cannot generate for my world

[Stiingrae]

I am trying to run Subterranea and Giant Caves on my Bukkit server, but every time i start the server it gives me an concerning Subterranea, and i cannot find a resolution to it.

Here is the error i get:

[SEVERE] [Subterranea] Could not set generator for default world 'world': Plugins 'Subterranea v1.6.4-R3' lacks a default world generator