17:44:40 [SEVERE] Could not pass event CUSTOM_EVENT to Heroes
java.lang.NoClassDefFoundError: com/herocraftonline/dev/heroes/api/WeaponDamageE
vent
        at com.herocraftonline.dev.heroes.skill.skills.SkillBackstab$CustomListe
ner.onCustomEvent(SkillBackstab.java:45)
        at org.bukkit.plugin.java.JavaPluginLoader$88.execute(JavaPluginLoader.j
ava:862)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:58)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:338)
        at com.herocraftonline.dev.heroes.persistence.Hero.gainExp(Hero.java:153
)
        at com.herocraftonline.dev.heroes.persistence.Hero.gainExp(Hero.java:102
)
        at com.herocraftonline.dev.heroes.HBlockListener.onBlockBreak(HBlockList
ener.java:84)
        at org.bukkit.plugin.java.JavaPluginLoader$37.execute(JavaPluginLoader.j
ava:497)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:58)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:338)
        at net.minecraft.server.ItemInWorldManager.c(ItemInWorldManager.java:157
)
        at net.minecraft.server.ItemInWorldManager.a(ItemInWorldManager.java:121
)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:481)
        at net.minecraft.server.Packet14BlockDig.a(SourceFile:42)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:89)
        at net.minecraft.server.NetworkListenThread.a(SourceFile:105)
        at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:454)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:363)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)