pvz count down error

[13:28:24] [Server thread/WARN]: [PvZ] Task #263 for PvZ v1.0 generated an exception
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
	at java.util.ArrayList.rangeCheck(Unknown Source) ~[?:1.7.0_51]
	at java.util.ArrayList.get(Unknown Source) ~[?:1.7.0_51]
	at com.lactem.pvz.game.GameManager.calculateRow(GameManager.java:225) ~[?:?]
	at com.lactem.pvz.inventory.InventoryManager.givePlantInventory(InventoryManager.java:180) ~[?:?]
	at com.lactem.pvz.game.GameManager.startGame(GameManager.java:81) ~[?:?]
	at com.lactem.pvz.tasks.Countdown.run(Countdown.java:23) ~[?:?]
	at org.bukkit.craftbukkit.v1_7_R2.scheduler.CraftTask.run(CraftTask.java:53) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]
	at org.bukkit.craftbukkit.v1_7_R2.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]
	at net.minecraft.server.v1_7_R2.MinecraftServer.v(MinecraftServer.java:590) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]
	at net.minecraft.server.v1_7_R2.DedicatedServer.v(DedicatedServer.java:250) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]
	at net.minecraft.server.v1_7_R2.MinecraftServer.u(MinecraftServer.java:548) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]
	at net.minecraft.server.v1_7_R2.MinecraftServer.run(MinecraftServer.java:459) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]
	at net.minecraft.server.v1_7_R2.ThreadServerApplication.run(SourceFile:618) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-14-g8f8716c-b3039jnks]