Bukkit

What is the issue?

Please provide any additional information below.

:554) [spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_45]
Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
        at java.util.ArrayList.rangeCheck(Unknown Source) ~[?:1.8.0_45]
        at java.util.ArrayList.get(Unknown Source) ~[?:1.8.0_45]
        at java.util.Collections$UnmodifiableList.get(Unknown Source) ~[?:1.8.0_
45]
        at com.gmail.nossr50.util.player.UserManager.getPlayer(UserManager.java:
94) ~[?:?]
        at com.gmail.nossr50.listeners.PlayerListener.onPlayerInteractLowest(Pla
yerListener.java:437) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor570.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1
.8.0_45]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_45]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:301) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        ... 17 more
[19:22:29 ERROR]: Could not pass event PlayerInteractEvent to mcMMO v1.5.00-b354
7
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:305) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:502) [spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:487) [spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        at org.bukkit.craftbukkit.v1_8_R2.event.CraftEventFactory.callPlayerInte
ractEvent(CraftEventFactory.java:227) [spigot-1.8.3.jar:git-Spigot-870264a-0a645
a2]
        at net.minecraft.server.v1_8_R2.PlayerInteractManager.interact(PlayerInt
eractManager.java:463) [spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
        at net.minecraft.server.v1_8_R2.PlayerConnection.a(PlayerConnection.java
:740) [spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]

>

Anyone know how to fix?