thanks Kyatric,
I checked that and saw this:
<img src="https://dl.dropboxusercontent.com/u/87325929/arcadeJsonProblem.png" border="0" />
I think the problem come from arcade because it seems there is a problem about json files. Each time i try to start (clicking on hardcore or peaceful buttons) i get another json file not found error.
I can share capx if needed.