Error on Client Side on Normal minecraft

[08:37:46] [Server thread/INFO] [TetraCraft]: Sub-Command: CommandModHelp has been registered
[08:37:46] [Server thread/ERROR] [FML]: Fatal errors were detected during the transition from SERVER_ABOUT_TO_START to SERVER_STARTING. Loading cannot continue
[08:37:46] [Server thread/ERROR] [FML]: 
	States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
	UCHIJAAA	mcp{9.19} [Minecraft Coder Pack] (minecraft.jar) 
	UCHIJAAA	FML{8.0.99.99} [Forge Mod Loader] (forge-1.9-12.16.1.1889.jar) 
	UCHIJAAA	Forge{12.16.1.1889} [Minecraft Forge] (forge-1.9-12.16.1.1889.jar) 
	UCHIJAAE	tetracraft{1.0.0} [TetraCraft] (TetraCraft-1.0.0.jar) 
[08:37:46] [Server thread/ERROR] [FML]: The following problems were captured during this phase
[08:37:46] [Server thread/ERROR] [FML]: Caught exception from tetracraft
java.lang.AbstractMethodError: novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.registerCommand(Lnet/minecraft/command/ICommand;)Lnet/minecraft/command/ICommand;
	at novaviper.tetracraft.common.init.ModCommands.addSubCommand(ModCommands.java:53) ~[ModCommands.class:?]
	at novaviper.tetracraft.common.init.ModCommands.registerSubCommands(ModCommands.java:33) ~[ModCommands.class:?]
	at novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.<init>(CommandTetraCraft.java:122) ~[CommandTetraCraft$SubCommandHandler.class:?]
	at novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.<init>(CommandTetraCraft.java:108) ~[CommandTetraCraft$SubCommandHandler.class:?]
	at novaviper.tetracraft.common.command.CommandTetraCraft.<init>(CommandTetraCraft.java:28) ~[CommandTetraCraft.class:?]
	at novaviper.tetracraft.common.init.ModCommands.load(ModCommands.java:24) ~[ModCommands.class:?]
	at novaviper.tetracraft.common.init.TetraCraft.serverStarting(TetraCraft.java:48) ~[TetraCraft.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_77]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_77]
	at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:561) ~[forge-1.9-12.16.1.1889.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_77]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_77]
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.post(EventBus.java:275) ~[guava-17.0.jar:?]
	at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:228) ~[forge-1.9-12.16.1.1889.jar:?]
	at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:206) ~[forge-1.9-12.16.1.1889.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_77]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_77]
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.post(EventBus.java:275) ~[guava-17.0.jar:?]
	at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:135) [LoadController.class:?]
	at net.minecraftforge.fml.common.Loader.serverStarting(Loader.java:815) [Loader.class:?]
	at net.minecraftforge.fml.common.FMLCommonHandler.handleServerStarting(FMLCommonHandler.java:284) [FMLCommonHandler.class:?]
	at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:121) [byn.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_77]
[08:37:46] [Server thread/ERROR] [FML]: A fatal exception occurred during the server starting event
net.minecraftforge.fml.common.LoaderException: java.lang.AbstractMethodError: novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.registerCommand(Lnet/minecraft/command/ICommand;)Lnet/minecraft/command/ICommand;

	at net.minecraftforge.fml.common.LoadController.transition(LoadController.java:179) ~[LoadController.class:?]
	at net.minecraftforge.fml.common.Loader.serverStarting(Loader.java:816) [Loader.class:?]
	at net.minecraftforge.fml.common.FMLCommonHandler.handleServerStarting(FMLCommonHandler.java:284) [FMLCommonHandler.class:?]
	at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:121) [byn.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_77]
Caused by: java.lang.AbstractMethodError: novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.registerCommand(Lnet/minecraft/command/ICommand;)Lnet/minecraft/command/ICommand;
	at novaviper.tetracraft.common.init.ModCommands.addSubCommand(ModCommands.java:53) ~[ModCommands.class:?]
	at novaviper.tetracraft.common.init.ModCommands.registerSubCommands(ModCommands.java:33) ~[ModCommands.class:?]
	at novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.<init>(CommandTetraCraft.java:122) ~[CommandTetraCraft$SubCommandHandler.class:?]
	at novaviper.tetracraft.common.command.CommandTetraCraft$SubCommandHandler.<init>(CommandTetraCraft.java:108) ~[CommandTetraCraft$SubCommandHandler.class:?]
	at novaviper.tetracraft.common.command.CommandTetraCraft.<init>(CommandTetraCraft.java:28) ~[CommandTetraCraft.class:?]
	at novaviper.tetracraft.common.init.ModCommands.load(ModCommands.java:24) ~[ModCommands.class:?]
	at novaviper.tetracraft.common.init.TetraCraft.serverStarting(TetraCraft.java:48) ~[TetraCraft.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_77]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_77]
	at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:561) ~[forge-1.9-12.16.1.1889.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_77]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_77]
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.post(EventBus.java:275) ~[guava-17.0.jar:?]
	at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:228) ~[LoadController.class:?]
	at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:206) ~[LoadController.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_77]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_77]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_77]
	at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304) ~[guava-17.0.jar:?]
	at com.google.common.eventbus.EventBus.post(EventBus.java:275) ~[guava-17.0.jar:?]
	at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:135) ~[LoadController.class:?]
	at net.minecraftforge.fml.common.Loader.serverStarting(Loader.java:815) ~[Loader.class:?]
	... 4 more
[08:37:46] [Server thread/INFO]: Stopping server
[08:37:46] [Server thread/INFO]: Saving players
[08:37:46] [Server thread/INFO]: Saving worlds
[08:37:46] [Server thread/INFO]: Saving chunks for level 'New World'/Overworld
[08:37:56] [Server thread/INFO]: Saving chunks for level 'New World'/Nether
[08:37:56] [Server thread/INFO]: Saving chunks for level 'New World'/The End
[08:37:58] [Server thread/INFO] [FML]: Unloading dimension 0
[08:37:58] [Server thread/INFO] [FML]: Unloading dimension -1
[08:37:58] [Server thread/INFO] [FML]: Unloading dimension 1
[08:37:58] [Server thread/INFO] [FML]: Applying holder lookups
[08:37:58] [Server thread/INFO] [FML]: Holder lookups applied
[08:37:58] [Server thread/INFO] [FML]: The state engine was in incorrect state ERRORED and forced into state SERVER_STOPPED. Errors may have been discarded.
[08:37:58] [Server thread/INFO] [FML]: The state engine was in incorrect state ERRORED and forced into state AVAILABLE. Errors may have been discarded.
[08:45:12] [Client thread/INFO]: Stopping!
[08:45:13] [Client thread/INFO]: SoundSystem shutting down...
[08:45:13] [Client thread/WARN]: Author: Paul Lamb, www.paulscode.com