error

12:54:15 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'heal
' in plugin PlayerCommands v1.1
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:19
2)
        at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchCommand(CraftServe
r.java:528)
        at net.minecraft.server.v1_6_R3.PlayerConnection.handleCommand(PlayerCon
nection.java:968)
        at net.minecraft.server.v1_6_R3.PlayerConnection.chat(PlayerConnection.j
ava:886)
        at net.minecraft.server.v1_6_R3.PlayerConnection.a(PlayerConnection.java
:837)
        at net.minecraft.server.v1_6_R3.Packet3Chat.handle(SourceFile:49)
        at net.minecraft.server.v1_6_R3.NetworkManager.b(NetworkManager.java:296
)
        at net.minecraft.server.v1_6_R3.PlayerConnection.e(PlayerConnection.java
:116)
        at net.minecraft.server.v1_6_R3.ServerConnection.b(SourceFile:37)
        at net.minecraft.server.v1_6_R3.DedicatedServerConnection.b(SourceFile:3
0)
        at net.minecraft.server.v1_6_R3.MinecraftServer.t(MinecraftServer.java:5
92)
        at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:2
27)
        at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:4
88)
        at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java
:421)
        at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:5
83)
Caused by: java.lang.IllegalArgumentException: File cannot be null
        at org.apache.commons.lang.Validate.notNull(Validate.java:203)
        at org.bukkit.configuration.file.YamlConfiguration.loadConfiguration(Yam
lConfiguration.java:170)
        at org.bukkit.plugin.java.JavaPlugin.reloadConfig(JavaPlugin.java:117)
        at org.bukkit.plugin.java.JavaPlugin.getConfig(JavaPlugin.java:111)
        at me.kait18.playercommands.commands.heal.onCommand(heal.java:15)
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
        ... 15 more