But you are forgetting that few thousand years after landing on earth the last Ice age starts, and the only habitable spots on the earth was equatorial Africa and south America.
The ice age would have disrupted many of the colonial settlements reducing the chances of them to develop any kind of advanced infer structure.
Just because some of them had knowledge of advanced science (Baltar)doesn't mean they would have brought the earth in to the technological level of the 21st century with in a few hundred years, and With out the infer structure the knowledge of Tilium Reactors would be useless.
The only advanced scientific knowledge would be applicable would be medicine (surgery and pharmacology) even that would be limited do to the lack of equipment and would not last very long with out a teaching program to train more.
If you divide the thirty some thousand people in to twelve groups you would get like three thousand per group so unless they are able to create a viable settlement with in a few years each would be doomed to extinction because they are not accustomed to a hunter gatherer life style.
The local enviroment would not be able to provide for the three thousand people to servive on hunting, and fishing. They would need to establish farming and animal husbandry in order to servive longer than a few years.