yop, mon jeu minecraft marche niquel avec le launcher vanilla, mais avec le launcher lifecraft, ils me disent "Error: A JNI error has occured, please check your installation and try again", puis "A Java Exception has occured", j'ai copier les logs de la console et voila ce que sa donne :

-----Launcher-----

[20:35:39][INFO]: OS Name == Windows 8.1
[20:35:39][INFO]: OS Version == 6.3
[20:35:39][INFO]: OS Arch == x86
[20:35:39][INFO]: Java Version == 1.8.0_40
[20:35:39][INFO]: Java Vendor == Oracle Corporation
[20:35:39][INFO]: Java Arch == 32
[20:35:39][INFO]: Vérification en cours..
[20:35:39][INFO]: --------------TheLauncherMine---------------
[20:35:39][INFO]: Launcher Build: B103 - 29.12.14_20:17:38
[20:35:39][INFO]: ---------------------------------------------
[20:35:39][CONFIG]: Lecture du Profil en cours..
[20:35:39][SEVERE]: Tentative de récupération de l'avatar pour: Herebus83...
[20:35:39][INFO]: Récupération de l'avatar complétée pour ..
[20:36:02][INFO]: Vérification du token.
Herebus83
6aaaccf3084b4d74a6ec5ae1d8f38301
759750f6-29c0-4597-91d6-745e7af03e51
[20:36:02][SEVERE]: Tentative de récupération de l'avatar pour: Herebus83...
[20:36:02][INFO]: Récupération de l'avatar complétée pour ..
[20:36:02][INFO]: Lecture des informations de mise à jour.
[20:36:02][INFO]: Vérification du dossier 'cache'.
[20:36:02][INFO]: Vérification du dossier 'assets'.
[20:36:02][INFO]: Vérification du dossier 'libraries'.
[20:36:02][INFO]: Vérification du dossier 'bin'.
[20:36:02][INFO]: Vérification du dossier 'natives'.
[20:36:03][INFO]: Libs manquant ..
[20:36:03][INFO]: Téléchargement des executables
DOWNLOAD IN PROGRESS : 'http://static.lifecraft.fr/launcher/jars.zip'
[20:36:09][INFO]: Extraction des executables
EXTRACT IN PROGRESS : C:\Users\julia_000\AppData\Roaming\.lifecraft\jars.lcp
C:\Users\julia_000\AppData\Roaming\.lifecraft\jars.lcp
[20:36:09][INFO]: Téléchargement des libs
DOWNLOAD IN PROGRESS : 'http://static.lifecraft.fr/launcher/libs.zip'
[20:36:17][INFO]: Extraction des libs
EXTRACT IN PROGRESS : C:\Users\julia_000\AppData\Roaming\.lifecraft\libraries.lcp
C:\Users\julia_000\AppData\Roaming\.lifecraft\libraries.lcp

-----Client-----

JavaProcessLauncher[commands=[-Dlog4j.configurationFile=C:\Users\julia_000\AppData\Roaming\.lifecraft\log4j2.xml, -Djava.library.path=C:\Users\julia_000\AppData\Roaming\.lifecraft\bin\natives\, -Xmx1024M, -cp, C:\Users\julia_000\AppData\Roaming\.lifecraft\bin\minecraft.jar, -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump, net.minecraft.client.main.Main, --username, Herebus83, --version, 1.7.2, --gameDir, C:\Users\julia_000\AppData\Roaming\.lifecraft, --uuid, ebb1dc0922d54acb8630e435674c07ac, --accessToken, 6aaaccf3084b4d74a6ec5ae1d8f38301, --assetsDir, C:\Users\julia_000\AppData\Roaming\.lifecraft\assets], java=C:\Program Files (x86)\Java\jre1.8.0_40\bin\javaw.exe]
Exception in thread "main" java.lang.NoClassDefFoundError: joptsimple/OptionSpec
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
at java.lang.Class.privateGetMethodRecursive(Unknown Source)
at java.lang.Class.getMethod0(Unknown Source)
at java.lang.Class.getMethod(Unknown Source)
at sun.launcher.LauncherHelper.validateMainClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Caused by: java.lang.ClassNotFoundException: joptsimple.OptionSpec
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 7 more