Plugin Help Various essential commands don't work. 1.12

So I have recently just updated my server to 1.12, and that required me reinstalling some plugins. After updating the server, I had tried to do /spawn, but it didn't work. I then went onto console to try and get it to work to which this happened: http://prntscr.com/fibzyi
Another two commands that seem not to work are /kill and /suicide
Kill: http://prntscr.com/fic0g2

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java.lang.NoSuchMethodError: org.bukkit.event.entity.EntityDamageEvent.<init>(Lorg/bukkit/entity/Entity;Lorg/bukkit/event/entity/EntityDamageEvent$DamageCause;I)V at com.earth2me.essentials.commands.Commandkill.updatePlayer(Commandkill.java:37) ~[Essentials-2.x-SNAPSHOT.jar:?] at com.earth2me.essentials.commands.EssentialsLoopCommand.loopOnlinePlayers(EssentialsLoopCommand.java:132) ~[Essentials-2.x-SNAPSHOT.jar:?] at com.earth2me.essentials.commands.Commandkill.run(Commandkill.java:26) ~[Essentials-2.x-SNAPSHOT.jar:?] at com.earth2me.essentials.commands.EssentialsCommand.run(EssentialsCommand.java:192) ~[Essentials-2.x-SNAPSHOT.jar:?] at com.earth2me.essentials.Essentials.onCommandEssentials(Essentials.java:523) [Essentials-2.x-SNAPSHOT.jar:?] at com.earth2me.essentials.Essentials.onCommand(Essentials.java:402) [Essentials-2.x-SNAPSHOT.jar:?] at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:140) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:622) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchServerCommand(CraftServer.java:608) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at net.minecraft.server.v1_12_R1.DedicatedServer.aP(DedicatedServer.java:403) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:367) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:650) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:554) [craftbukkit-1.12.jar:git-Bukkit-bb4ae3b] at java.lang.Thread.run(Thread.java:745) [?:1.8.0_112]

(Spoiler is the error message)
and I don't think I can show the /suicide message, as when I enter it it literally does nothing. It doesn't show anything in chat or console

If it helps, another thing that seems to happen a lot of times is: http://prntscr.com/fic1wk
The crossed out parts being the server IP.
I use server.pro, if that helps.

 

If your still using the basic essentials on 1.11.X then switch to essentialsX because the older essentials is no longer being supported

 

@TortoiseTyler
The error message is saying it cannot find EntityDamageEvent, something that bukkit should still have. Try re-compiling the bukkit jar and see if that fixes the problem.

 

How exactly do I re-compile the bukkit jar?

 

@TortoiseTyler
[Edit] Just saw you are using server.pro. Instead of recompiling, either try doing a full restart of the server to see if that fixes the problem. If that does not work, then try contacting the hosting site and ask them to verify/update the jar.