Well, the 2004 movie takes place in the past, right? And the Turaga were Toa on Metru Nui, right? And yet the Turaga still say that Mata Nui is the only island on the planet, when they've been to another one. Is there something wrong with this or am I just totaly wrong?

I don't recall the Turaga ever saying that Mata Nui is the only Island. It makes since for there to be more than one island on an entire planet.
Anyway we do have an Official 04/Metru Nui theory topic

Oh, sorry. I will take this to that topic.

Please use the official Metru Nui topic.

-Kaiapu