Could not load 'plugins\mcore.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/v1_7_R1/PlayerInventory
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-1356]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[spigot.jar:git-Spigot-1356]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot.jar:git-Spigot-1356]
	at org.bukkit.craftbukkit.v1_7_R2.CraftServer.loadPlugins(CraftServer.java:356) [spigot.jar:git-Spigot-1356]
	at net.minecraft.server.v1_7_R2.DedicatedServer.init(DedicatedServer.java:135) [spigot.jar:git-Spigot-1356]
	at net.minecraft.server.v1_7_R2.MinecraftServer.run(MinecraftServer.java:440) [spigot.jar:git-Spigot-1356]
	at net.minecraft.server.v1_7_R2.ThreadServerApplication.run(SourceFile:618) [spigot.jar:git-Spigot-1356]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_7_R1/PlayerInventory
	at com.massivecraft.mcore.MCore.getMCoreGsonBuilder(MCore.java:83) ~[?:?]
	at com.massivecraft.mcore.MCore.<clinit>(MCore.java:68) ~[?:?]
	at java.lang.Class.forName0(Native Method) ~[?:1.7.0]
	at java.lang.Class.forName(Unknown Source) ~[?:1.7.0]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[spigot.jar:git-Spigot-1356]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:127) ~[spigot.jar:git-Spigot-1356]
	... 6 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_7_R1.PlayerInventory
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:67) ~[spigot.jar:git-Spigot-1356]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) ~[spigot.jar:git-Spigot-1356]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0]
	at com.massivecraft.mcore.MCore.getMCoreGsonBuilder(MCore.java:83) ~[?:?]
	at com.massivecraft.mcore.MCore.<clinit>(MCore.java:68) ~[?:?]
	at java.lang.Class.forName0(Native Method) ~[?:1.7.0]
	at java.lang.Class.forName(Unknown Source) ~[?:1.7.0]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[spigot.jar:git-Spigot-1356]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:127) ~[spigot.jar:git-Spigot-1356]
	... 6 more