nearest we can figure, the movie is either the "legend" retelling of the story OR the movie is the first time these characters were in this cycle and because they screwed up, they all came back and had a chance to redo it which were the events in the TV series. There's stuff to support the later idea, like the megaroad leaving and how the planet gets changed. If you remember in the TV show they talk about how they "colonized" the planet.