This errors come up when player play a bit, do some quests and turn in and log off. Log back in and this error comes up.

[23:54:38 ERROR]: Could not pass event PlayerJoinEvent to EpicQuest v3.5.2
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:305) ~[spigot_server.jar:git-Spigot-13716d9-0899683]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62) ~[spigot_server.jar:git-Spigot-13716d9-0899683]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:502) [spigot_server.jar:git-Spigot-13716d9-0899683]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:487) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.PlayerList.onPlayerJoin(PlayerList.java:
263) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.PlayerList.a(PlayerList.java:148) [spigo
t_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.LoginListener.b(LoginListener.java:109)
[spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.LoginListener.c(LoginListener.java:41) [
spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.NetworkManager.a(NetworkManager.java:159
) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.ServerConnection.c(ServerConnection.java
:82) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:7
85) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:3
16) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:6
23) [spigot_server.jar:git-Spigot-13716d9-0899683]
at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java
:526) [spigot_server.jar:git-Spigot-13716d9-0899683]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_25]
Caused by: java.lang.NullPointerException
at randy.engine.EpicPlayer.giveQuestBook(EpicPlayer.java:104) ~[?:?]
at randy.filehandlers.SaveLoader.loadPlayer(SaveLoader.java:479) ~[?:?]
at randy.listeners.PlayerJoinListener.onPlayerJoin(PlayerJoinListener.ja
va:20) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0
_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0
_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1
.8.0_25]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_25]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:301) ~[spigot_server.jar:git-Spigot-13716d9-0899683]
... 14 more

This error seems to be random.

This might've fixed it: e259336