killrank 1.5 error

013-03-19 16:01:31 [INFO] This server is running CraftBukkit version git-Bukkit-1.4.7-R1.0-45-g5c7d0bb-b2681jnks (MC: 1.5) (Implementing API version 1.5-R0.1-SNAPSHOT)
2013-03-19 16:01:31 [SEVERE] Could not load 'plugins\KillRank_v1.7.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.ClassNotFoundException: killrank.KillRank
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184)
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
	at org.bukkit.craftbukkit.v1_5_R1.CraftServer.loadPlugins(CraftServer.java:239)
	at org.bukkit.craftbukkit.v1_5_R1.CraftServer.<init>(CraftServer.java:217)
	at net.minecraft.server.v1_5_R1.PlayerList.<init>(PlayerList.java:56)
	at net.minecraft.server.v1_5_R1.DedicatedPlayerList.<init>(SourceFile:11)
	at net.minecraft.server.v1_5_R1.DedicatedServer.init(DedicatedServer.java:105)
	at net.minecraft.server.v1_5_R1.MinecraftServer.run(MinecraftServer.java:381)
	at net.minecraft.server.v1_5_R1.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.ClassNotFoundException: killrank.KillRank
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(Unknown Source)
	at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:80)
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Unknown Source)
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173)
	... 9 more