[17:23:38] [Server thread/ERROR]: Could not load 'plugins\VirtualPlayers.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/v1_6_R3/Entity
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184) ~[craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305) ~[craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugins(CraftServer.java:255) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.<init>(CraftServer.java:233) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at net.minecraft.server.v1_7_R1.PlayerList.<init>(PlayerList.java:63) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at net.minecraft.server.v1_7_R1.DedicatedPlayerList.<init>(SourceFile:14) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at net.minecraft.server.v1_7_R1.DedicatedServer.init(DedicatedServer.java:126) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:420) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_6_R3/Entity
	at java.lang.Class.forName0(Native Method) ~[?:1.7.0_45]
	at java.lang.Class.forName(Unknown Source) ~[?:1.7.0_45]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173) ~[craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	... 9 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_6_R3.Entity
	at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70) ~[craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53) ~[craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_45]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_45]
	at java.lang.Class.forName0(Native Method) ~[?:1.7.0_45]
	at java.lang.Class.forName(Unknown Source) ~[?:1.7.0_45]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173) ~[craftbukkit.jar:git-Bukkit-1.6.4-R2.0-38-g4b4e2cc-b2953jnks]
	... 9 more