AUTORANK VOLTZ NEED HELP!!!

IF YOU KNOW MY ERROR HERE THEN PLEASE CONTACT ME ON SKYPE: stobbzy12, THIS IS FOR AUTORANK FOR A VOLTZ SERVER!!

2015-05-09 18:03:01 [SEVERE] org.apache.commons.lang.UnhandledException: Plugin Autorank v3.5.1 generated an exception while executing task 230
at org.bukkit.craftbukkit.v1_5_R3.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: java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()Ljava/util/Collection;
at me.armar.plugins.autorank.playtimes.PlaytimesUpdate.updateMinutesPlayed(PlaytimesUpdate.java:68)
at me.armar.plugins.autorank.playtimes.PlaytimesUpdate.run(PlaytimesUpdate.java:30)
at org.bukkit.craftbukkit.v1_5_R3.scheduler.CraftTask.run(CraftTask.java:58)
at org.bukkit.craftbukkit.v1_5_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
... 3 more




ALSO THIS IS MY SETUP FOR ADV CONFIG:
#                                                                           #
#                   Autorank 2 Advanced Config                              #
#                                                                           #
#   Please use the SimpleConfig unless you know what you are doing and      #
#   need functionality that the SimpleConfig doesn't provide.               #
#                                                                           #
#############################################################################

ranks:
    Default:
        requirements:
            time:
                value: 1m
        results:
            rank change: Default;Power
            command: 'say &p just got a promotion; broadcast &p has just been promoted to Power!'
            message: 'Congratulations, you are now in the group Power!.'
    Power:
        requirements:
            time:
                value: 3h
        results:
            rank change: Power;Watt
            command: 'say &p has just been promoted to Watt!'
            message: 'Congratulations, you are now a Watt.'
    Watt:
        requirements:
            time:
                value: 4h
        results:
            rank change: Watt;Amp
            command: 'say &p has just been promoted to Amp!'
            message: 'Congratulations, you are now an Amp!.'
    Amp:
        requirements:
            time:
                value: 6h
        results:
            rank change: Amp;Mega-Watt
            command: 'say &p has just been promoted to Mega-Watt!'
            message: 'Congratulations, you are now an Mega-Watt!.'
# new requirements and results can be added by other plugins that hook into the Autorank API
# these are the ones that are included in the main plugin: