There is a difference between creating a new game and creating a new world. Once you create a world, you can play as many different save games on that world as you want.
It really sounds like you are trying to create a new game on an old world. Volalha is an old world created in a previous version. You are trying to create a new GAME on the old WORLD.
You need to select new random world and enter something completely different that you have never used before to generate a world and type that into the seed name. That will generate a new world. You can then choose that world (it will be named something not Volalha, pregen 1,2,3 or navezgane), and start as many new games named whatever you want on that new world.
If you want to see what your new world looks like, you can instead go to Editing Tools instead of New Game. Type something new and completely different than anything you have ever used before to generate a new world. Wait until it is done. You can then see your world. The game will give it some sort of name (like whatever county). When you go to new game, pick the new world you just generated to start that game on.