uSB error

[08:47:19] [Craft Scheduler Thread - 658/WARN]: Exception in thread "Craft Scheduler Thread - 658"
[08:47:19] [Craft Scheduler Thread - 658/WARN]: org.apache.commons.lang.UnhandledException: Plugin uSkyBlock v2.2-HF4 generated an exception while executing task 418846
	at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:56)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: org.bukkit.plugin.IllegalPluginAccessException: Plugin attempted to register task while disabled
	at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftScheduler.validate(CraftScheduler.java:400)
	at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftScheduler.runTaskTimerAsynchronously(CraftScheduler.java:141)
	at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftScheduler.runTaskLaterAsynchronously(CraftScheduler.java:115)
	at us.talabrek.ultimateskyblock.async.AsyncBalancedExecutor.doLater(AsyncBalancedExecutor.java:16)
	at us.talabrek.ultimateskyblock.async.AbstractBalancedExecutor$IncrementalExecution.run(AbstractBalancedExecutor.java:127)
	at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftTask.run(CraftTask.java:71)
	at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
	... 3 more