I found out where the problems, there is a conflict between mods BoulderCo and UniverseReplacer. Sido's Urania works perfectly with these mods separately. BoulderCo seem to handle textures replacement, is it possible to use a Skybox with it?
The game crash using this mod with KW Rocketry ! I dont have this problem using only Krag's Planet Factory. (Le jeu plante en ayant ce mod et KW Rocketry, je n'ai pas ce problème en utilisant uniquement Krag's Planet Factory sans Urania. Il y a une solution ?)