Creating world with seed and map world "QUATREPOINTDEUX" fails

What I expected to happen was...:
Create a new world with the name "QUATREPOINTDEUX" without quotes and the seed "QUATREPOINTDEUX" without quotes.

What actually happened was...:
There is the normal generation screen with the mentions "Loading world" and "Converting world" but nothing happens after. I mean the game stops at this screen.

Steps to Reproduce:
1- Click on "Singleplayer"
2- Click on "Create a new world"
3- Write QUATREPOINTDEUX as the World name
4- Go to "More world options" and type QUATREPOINTDEUX as seed.
5- Click on Create new world.