GAListener Error

[12:11:49] [Server thread/INFO]: [GAListener] Vote received on PlanetMinecraft.com for Player: Syresiath
[12:11:49] [Craft Scheduler Thread - 1734/WARN]: Exception in thread "Craft Scheduler Thread - 1734"
[12:11:49] [Craft Scheduler Thread - 1734/WARN]: org.apache.commons.lang.UnhandledException: Plugin GAListener v1.3.1 generated an exception while executing task 14992
	at org.bukkit.craftbukkit.v1_9_R2.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:56)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()[Lorg/bukkit/entity/Player;
	at com.swifteh.GAL.RewardTask.run(RewardTask.java:37)
	at org.bukkit.craftbukkit.v1_9_R2.scheduler.CraftTask.run(CraftTask.java:71)
	at org.bukkit.craftbukkit.v1_9_R2.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
	... 3 more