Essentials Error

My console keeps spitting the same line of code out at me, and it has to do with essentials. Can someone tell me what this means and how to fix it. Thanks!

Code:

2012-10-30 13:09:03 [WARNING] [Essentials] Task #70 for Essentials v2.9.3 generated an exception
java.lang.NoClassDefFoundError: org/anjocaido/groupmanager/dataholder/worlds/WorldsHolder
    at com.earth2me.essentials.perm.GroupManagerHandler.getHandler(GroupManagerHandler.java:105)
    at com.earth2me.essentials.perm.GroupManagerHandler.hasPermission(GroupManagerHandler.java:68)
    at com.earth2me.essentials.perm.PermissionsHandler.hasPermission(PermissionsHandler.java:75)
    at com.earth2me.essentials.User.isAuthorized(User.java:84)
    at com.earth2me.essentials.User.checkActivity(User.java:553)
    at com.earth2me.essentials.EssentialsTimer.run(EssentialsTimer.java:49)
    at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:53)
    at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345)
    at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:522)
    at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:215)
    at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:486)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:419)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:818)

 

necrodoom

 

well first off there is a New Recommended build for essentials so update to that here
http://dev.bukkit.org/server-mods/essentials/files/169-essentials-2-9-4/
if you want to update to the lastest beta build here
http://dev.bukkit.org/server-mods/essentials/files/171-essentials-pre2-9-5-0/

 

do as jacklin213 said, and RESTART, dont /reload

 

As in use /stop then start not /reload