[17:00:05] [Server thread/ERROR]: Could not load 'plugins\Assassination_v1.5.8.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.IllegalArgumentException: Plugin already initialized!
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:137) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:313) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:236) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugins(CraftServer.java:350) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.<init>(CraftServer.java:312) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.PlayerList.<init>(PlayerList.java:63) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.DedicatedPlayerList.<init>(SourceFile:14) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.DedicatedServer.init(DedicatedServer.java:126) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:424) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
Caused by: java.lang.IllegalArgumentException: Plugin already initialized!
	at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:98) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:59) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at pl.ZamorekPL.Assassination.Main.<init>(Main.java:35) ~[?:?]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.7.0_45]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.7.0_45]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.7.0_45]
	at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.7.0_45]
	at java.lang.Class.newInstance(Unknown Source) ~[?:1.7.0_45]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:52) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	... 9 more
Caused by: java.lang.IllegalStateException: Initial initialization
	at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:101) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:59) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at pl.ZamorekPL.Assassination.Main.<init>(Main.java:35) ~[?:?]
	at pl.ZamorekPL.Assassination.Main.<clinit>(Main.java:37) ~[?:?]
	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.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[cb.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	... 9 more