java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: net/minecraft/client/model/ModelBiped
at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_72]
at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_72]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) [h.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:668) [MinecraftServer.class:?]
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:387) [ld.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:613) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:471) [MinecraftServer.class:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_72]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/model/ModelBiped
at com.vicmatskiv.weaponlib.EntityShellCasing.setPositionAndDirection(EntityShellCasing.java:78) ~[EntityShellCasing.class:?]
at com.vicmatskiv.weaponlib.Weapon$Builder.lambda$build$37(Weapon.java:652) ~[Weapon$Builder.class:?]
at com.vicmatskiv.weaponlib.WeaponFireAspect.serverFire(WeaponFireAspect.java:317) ~[WeaponFireAspect.class:?]
at com.vicmatskiv.weaponlib.WeaponFireAspect.serverFire(WeaponFireAspect.java:286) ~[WeaponFireAspect.class:?]
at com.vicmatskiv.weaponlib.TryFireMessageHandler.lambda$onCompatibleMessage$360(TryFireMessageHandler.java:28) ~[TryFireMessageHandler.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_72]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_72]
at net.minecraft.util.Util.func_181617_a(SourceFile:45) ~[h.class:?]
... 5 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.client.model.ModelBiped
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:101) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_72]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_72]
at com.vicmatskiv.weaponlib.EntityShellCasing.setPositionAndDirection(EntityShellCasing.java:78) ~[EntityShellCasing.class:?]
at com.vicmatskiv.weaponlib.Weapon$Builder.lambda$build$37(Weapon.java:652) ~[Weapon$Builder.class:?]
at com.vicmatskiv.weaponlib.WeaponFireAspect.serverFire(WeaponFireAspect.java:317) ~[WeaponFireAspect.class:?]
at com.vicmatskiv.weaponlib.WeaponFireAspect.serverFire(WeaponFireAspect.java:286) ~[WeaponFireAspect.class:?]
at com.vicmatskiv.weaponlib.TryFireMessageHandler.lambda$onCompatibleMessage$360(TryFireMessageHandler.java:28) ~[TryFireMessageHandler.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_72]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_72]
at net.minecraft.util.Util.func_181617_a(SourceFile:45) ~[h.class:?]
... 5 more

si quelqu'un peux m'aidez svp