error

[21:34:10] [Server thread/ERROR]: Could not pass event PlayerJoinEvent to BMSkyBlock v1.0org.bukkit.event.EventExceptionat org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.PlayerList.onPlayerJoin(PlayerList.java:298) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.PlayerList.a(PlayerList.java:157) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.LoginListener.b(LoginListener.java:144) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.LoginListener.c(LoginListener.java:54) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.NetworkManager.a(NetworkManager.java:231) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.ServerConnection.c(ServerConnection.java:148) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:814) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at java.lang.Thread.run(Thread.java:748) [?:1.8.0_141]Caused by: java.lang.NoClassDefFoundError: me/clip/voteparty/VotePartyAPIat com.benzimmer123.scoreboard.ScoreboardManager.updateScoreboard(ScoreboardManager.java:60) ~[?:?]at com.benzimmer123.scoreboard.ScoreboardManager.PlayerJoin(ScoreboardManager.java:30) ~[?:?]at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_141]at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_141]at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_141]at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_141]at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]... 14 moreCaused by: java.lang.ClassNotFoundException: me.clip.voteparty.VotePartyAPIat java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[?:1.8.0_141]at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:101) ~[spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_141]at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_141]at com.benzimmer123.scoreboard.ScoreboardManager.updateScoreboard(ScoreboardManager.java:60) ~[?:?]at com.benzimmer123.scoreboard.ScoreboardManager.PlayerJoin(ScoreboardManager.java:30) ~[?:?]at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_141]at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_141]at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_141]at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_141]at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigotmc-1.8.8-R0.1.jar:git-Spigot-e4d4710-e1ebe52]... 14 more