Skin-Manager Error

Header :
java.io.FileInputStream.open(Native Method)
java.io.FileInputStream.<init>(FileInputStream.java:146)
java.util.Scanner.<init>(Scanner.java:656)
me.kitt3120.skinmanager.Core.getNewestVersion(Core.java:151)
me.kitt3120.skinmanager.Core.isUpdateAvailable(Core.java:139)
me.kitt3120.skinmanager.Core.onJoin(Core.java:668)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:606)
org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306)
org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502)
org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487)
net.minecraft.server.v1_8_R3.PlayerList.onPlayerJoin(PlayerList.java:296)
net.minecraft.server.v1_8_R3.PlayerList.a(PlayerList.java:156)
net.minecraft.server.v1_8_R3.LoginListener.b(LoginListener.java:144)
net.minecraft.server.v1_8_R3.LoginListener.c(LoginListener.java:54)
net.minecraft.server.v1_8_R3.NetworkManager.a(NetworkManager.java:231)
net.minecraft.server.v1_8_R3.ServerConnection.c(ServerConnection.java:148)
net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:817)
net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367)
net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657)
net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560)
java.lang.Thread.run(Thread.java:745)
Next :

plugins/SkinManager/UpdateInfo.txt (No such file or directory)
java.io.FileNotFoundException: plugins/SkinManager/UpdateInfo.txt (No such file or directory)