I am experiencing a crash upon launch of biomes o plenty

Forge version - forge 1.9.4-12.17.0.1909-1.9.4
Biomes o plenty version - BiomesOPlenty-1.9.4-4.1.0.2023

The crash happens with both optifine installed and without it installed

Crash Report -

---- Minecraft Crash Report ----
// There are four lights!

Time: 30/05/16 13:16
Description: There was a severe problem during mod loading that has caused the game to fail

net.minecraftforge.fml.common.LoaderException: java.lang.NoSuchMethodError: net.minecraftforge.common.util.EnumHelper.addArmorMaterial(Ljava/lang/String;Ljava/lang/String;I[IILnet/minecraft/util/SoundEvent;F)Lnet/minecraft/item/ItemArmor$ArmorMaterial;
at net.minecraftforge.fml.common.LoadController.transition(LoadController.java:179)
at net.minecraftforge.fml.common.Loader.preinitializeMods(Loader.java:587)
at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:249)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:437)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:349)
at net.minecraft.client.main.Main.main(SourceFile:124)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.NoSuchMethodError: net.minecraftforge.common.util.EnumHelper.addArmorMaterial(Ljava/lang/String;Ljava/lang/String;I[IILnet/minecraft/util/SoundEvent;F)Lnet/minecraft/item/ItemArmor$ArmorMaterial;
at biomesoplenty.common.init.ModItems.addArmorMaterial(ModItems.java:315)
at biomesoplenty.common.init.ModItems.registerItems(ModItems.java:210)
at biomesoplenty.common.init.ModItems.init(ModItems.java:148)
at biomesoplenty.core.BiomesOPlenty.preInit(BiomesOPlenty.java:72)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:561)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:228)
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:206)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:135)
at net.minecraftforge.fml.common.Loader.preinitializeMods(Loader.java:584)
... 10 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- System Details --
Details:
Minecraft Version: 1.9.4
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 115243504 bytes (109 MB) / 381599744 bytes (363 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP 9.28 Powered by Forge 12.17.0.1909 4 mods loaded, 4 mods active
States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
UCH mcp{9.19} Minecraft Coder Pack
UCH FML{8.0.99.99} Forge Mod Loader
UCH Forge{12.17.0.1909} Minecraft Forge
UCE BiomesOPlenty{4.1.0.2023} Biomes O' Plenty
Loaded coremods (and transformers):
GL info: ' Vendor: 'NVIDIA Corporation' Version: '4.5.0 NVIDIA 355.60' Renderer: 'GeForce GTX 750 Ti/PCIe/SSE2'

Hope someone can help

Update your Forge, you are using an outdated version.