error whitelist

[WARNING] Unexpected exception while parsing console command
org.bukkit.command.CommandException: Unhandled exception executing command 'whitelist' in plugin DynamicEffectWhitelist v1.5.1
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:166)
	at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:473)
	at org.bukkit.craftbukkit.CraftServer.dispatchServerCommand(CraftServer.java:469)
	at net.minecraft.server.MinecraftServer.b(MinecraftServer.java:596)
	at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:565)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
	at com.dynamiceffect.whitelist.DynamicEffectWhitelist.AddPlayerToWhitelist(DynamicEffectWhitelist.java:520)
	at com.dynamiceffect.whitelist.DynamicEffectWhitelist.CommandHandler(DynamicEffectWhitelist.java:127)
	at com.dynamiceffect.whitelist.DynamicEffectWhitelist.onCommand(DynamicEffectWhitelist.java:113)
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
	... 7 more