error 2 after using a couple commands

[10:45:47 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'sg' in plugin SurvivalGames v1.0.6
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot.jar:git-Spigot-1310]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:199) ~[spigot.jar:git-Spigot-1310]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchCommand(CraftServer.java:547) ~[spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.PlayerConnection.handleCommand(PlayerConnection.java:972) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.PlayerConnection.a(PlayerConnection.java:817) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.PacketPlayInChat.a(PacketPlayInChat.java:28) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.PacketPlayInChat.handle(PacketPlayInChat.java:65) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.NetworkManager.a(NetworkManager.java:147) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.ServerConnection.c(ServerConnection.java:77) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:698) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:273) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:560) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:467) [spigot.jar:git-Spigot-1310]
	at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [spigot.jar:git-Spigot-1310]
Caused by: java.lang.NullPointerException
	at net.shockverse.survivalgames.api.SGAPI.addPlayerToGame(SGAPI.java:243) ~[?:?]
	at net.shockverse.survivalgames.commands.SGCmd.onCommand(SGCmd.java:335) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot.jar:git-Spigot-1310]
	... 13 more