[19:52:24] [Server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: net/minecraft/client/model/ModelBiped
        at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_181]
        at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_181]
        at net.minecraft.util.Util.func_181617_a(Util.java:51) [h.class:?]
        at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:841) [MinecraftServer.class:?]
        at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:472) [nz.class:?]
        at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:778) [MinecraftServer.class:?]
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:632) [MinecraftServer.class:?]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_181]
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$359(TryFireMessageHandler.java:28) ~[TryFireMessageHandler.class:?]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_181]
        at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_181]
        at net.minecraft.util.Util.func_181617_a(Util.java:50) ~[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(Unknown Source) ~[?:1.8.0_181]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_181]
        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$359(TryFireMessageHandler.java:28) ~[TryFireMessageHandler.class:?]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_181]
        at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_181]
        at net.minecraft.util.Util.func_181617_a(Util.java:50) ~[h.class:?]
        ... 5 more
           模组是维克多现代战争 1.12.2     开一枪就跳一下这段 代码，服务器会卡
请求大佬解答！！！！

在服务器里面  一开  qiang   就报错

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