I Can't Get Anywhere Other Than the Fight Area On Pokemon Platinum in the Battle Zone. Help?

I beat the Pokemon League in Platinum. I went on the ship at Snowpoint City that takes you to the Battle Zone, and two people are blocking the ways to get to the other ares in the Battle Zone. I already got to the frontier, so I'm not talking about Volkner and Flint. How do you get to places like the Survival Area?