GUI shop error; If someone could help me.

I recently installed GUIshop but I have an issue with it.

When someone types /shop it comes up with this error in the console;

3.08 17:34:24 [Server] INFO ... 15 more
13.08 17:34:24 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at us.alreadycoded.shop.Shop.onCommand(Shop.java:100) ~[?:?]
13.08 17:34:24 [Server] INFO Caused by: java.lang.NoSuchFieldError: CHEST_OPEN
13.08 17:34:24 [Server] INFO at java.lang.Thread.run(Thread.java:745) [?:1.8.0_71]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:572) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:673) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:737) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.SystemUtils.a(SourceFile:45) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_71]
13.08 17:34:24 [Server] INFO at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_71]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.PlayerConnection.a(PlayerConnection.java:1186) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at net.minecraft.server.v1_10_R1.PlayerConnection.handleCommand(PlayerConnection.java:1351) [spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServer.java:646) ~[spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.10.2-20160713a.jar:git-Spigot-9797151-301db84]
13.08 17:34:24 [Server] INFO org.bukkit.command.CommandException: Unhandled exception executing command 'shop' in plugin GUIShop v2.1
13.08 17:34:24 [Server] ERROR null




It also comes up with "An internal error occured"