C:\Documents and Settings\utilisateur\Mes documents\My Games\Unreal Tournament 3\UTGame\Unpublished\CookedPC\CustomMaps
I hope someone can help me out

Edit***: LOL, I've been so stupid, it's very important to make a new folder that is named ¨published¨ and not ¨unpublished¨... It now works, I have made this thread for no reason, shame on me.