[17:05:53] [Server thread/FATAL] [minecraft/MinecraftServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: com/gamerforea/eventhelper/util/ItemInventoryValidator
        at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_222]
        at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_222]
        at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
        at org.spongepowered.common.SpongeImplHooks.onUtilRunTask(SpongeImplHooks.java:308) [SpongeImplHooks.class:1.12.2-2838-7.1.7-RC3926]
        at net.minecraft.server.MinecraftServer.redirect$onRun$zjd000(MinecraftServer.java:4716) [MinecraftServer.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:748) [?:1.8.0_222]
Caused by: java.lang.NoClassDefFoundError: com/gamerforea/eventhelper/util/ItemInventoryValidator
        at com.tattyseal.compactstorage.inventory.InventoryBackpack.<init>(InventoryBackpack.java:60) ~[InventoryBackpack.class:?]
        at com.tattyseal.compactstorage.GuiHandler.getServerGuiElement(GuiHandler.java:38) ~[GuiHandler.class:?]
        at net.minecraftforge.fml.common.network.NetworkRegistry.redirect$forgeImpl$updatePluginContainer$zpm000(NetworkRegistry.java:551) ~[NetworkRegistry.class:?]
        at net.minecraftforge.fml.common.network.NetworkRegistry.getRemoteGuiContainer(NetworkRegistry.java:253) ~[NetworkRegistry.class:?]
        at net.minecraftforge.fml.common.network.internal.FMLNetworkHandler.openGui(FMLNetworkHandler.java:88) ~[FMLNetworkHandler.class:?]
        at net.minecraft.entity.player.EntityPlayer.openGui(EntityPlayer.java:2550) ~[aed.class:?]
        at com.tattyseal.compactstorage.item.ItemBackpack.func_77659_a(ItemBackpack.java:42) ~[ItemBackpack.class:?]
        at net.minecraft.item.ItemStack.func_77957_a(ItemStack.java:217) ~[aip.class:?]
        at net.minecraft.server.management.PlayerInteractionManager.func_187250_a(PlayerInteractionManager.java:1025) ~[or.class:?]
        at net.minecraft.network.NetHandlerPlayServer.redirect$impl$checkStateAfter$zih000(NetHandlerPlayServer.java:2957) ~[pa.class:?]
        at net.minecraft.network.NetHandlerPlayServer.func_147346_a(NetHandlerPlayServer.java:765) ~[pa.class:?]
        at net.minecraft.network.play.client.CPacketPlayerTryUseItem.func_148833_a(SourceFile:32) ~[mb.class:?]
        at net.minecraft.network.play.client.CPacketPlayerTryUseItem.func_148833_a(SourceFile:9) ~[mb.class:?]
        at org.spongepowered.common.event.tracking.phase.packet.PacketPhaseUtil.onProcessPacket(PacketPhaseUtil.java:209) ~[PacketPhaseUtil.class:1.12.2-2838-7.1.7-RC3926]
        at net.minecraft.network.PacketThreadUtil$1.redirect$impl$redirectToPhaseTracker$zkp000(SourceFile:540) ~[hv$1.class:?]
        at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_222]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_222]
        at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
        ... 7 more