Using the keybinds does nothing and the console say this

[13:52:00] [Server thread/FATAL] [minecraft/MinecraftServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: net/minecraft/client/Minecraft
at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_345]
at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_345]
at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?]
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
at java.lang.Thread.run(Thread.java:750) [?:1.8.0_345]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/Minecraft
at com.tfar.dankstorage.util.Utils.toggle(Utils.java:39) ~[Utils.class:?]
at com.tfar.dankstorage.network.CMessageToggle$Handler.handle(CMessageToggle.java:58) ~[CMessageToggle$Handler.class:?]
at com.tfar.dankstorage.network.CMessageToggle$Handler.lambda$onMessage$0(CMessageToggle.java:47) ~[CMessageToggle$Handler.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_345]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_345]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
... 5 more

(End of log)