Console Output :: Error

[17:12:48 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'o' i
n plugin GUI v6.6.6
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[buk
kit-1.8.jar:git-Bukkit-33d5de3]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:14
0) ~[bukkit-1.8.jar:git-Bukkit-33d5de3]
        at org.bukkit.craftbukkit.v1_8_R1.CraftServer.dispatchCommand(CraftServe
r.java:625) ~[bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PlayerConnection.handleCommand(PlayerCon
nection.java:1058) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PlayerConnection.a(PlayerConnection.java
:919) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(SourceFile:37) [bukki
t-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(SourceFile:9) [bukkit
-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PacketHandleTask.run(SourceFile:13) [buk
kit-1.8.jar:git-Bukkit-33d5de3]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [
?:1.8.0_111]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_111]
        at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:6
56) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:2
84) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:6
09) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java
:517) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_111]
Caused by: java.lang.NullPointerException
        at ashwin.gui.GuiMain.onCommand(GuiMain.java:58) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[buk
kit-1.8.jar:git-Bukkit-33d5de3]
        ... 14 more
[17:12:59 INFO]: SocialNetwork issued server command: /opt
[17:12:59 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'opt'
 in plugin GUI v6.6.6
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[buk
kit-1.8.jar:git-Bukkit-33d5de3]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:14
0) ~[bukkit-1.8.jar:git-Bukkit-33d5de3]
        at org.bukkit.craftbukkit.v1_8_R1.CraftServer.dispatchCommand(CraftServe
r.java:625) ~[bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PlayerConnection.handleCommand(PlayerCon
nection.java:1058) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PlayerConnection.a(PlayerConnection.java
:919) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(SourceFile:37) [bukki
t-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PacketPlayInChat.a(SourceFile:9) [bukkit
-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.PacketHandleTask.run(SourceFile:13) [buk
kit-1.8.jar:git-Bukkit-33d5de3]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [
?:1.8.0_111]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_111]
        at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:6
56) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:2
84) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:6
09) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java
:517) [bukkit-1.8.jar:git-Bukkit-33d5de3]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_111]
Caused by: java.lang.NullPointerException
        at ashwin.gui.GuiMain.onCommand(GuiMain.java:50) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[buk
kit-1.8.jar:git-Bukkit-33d5de3]
        ... 14 more