Invalid Plugin exception

Whenever I run my server I am given this error upon loading:

Code:

[SEVERE] Could not load plugins\Tunnelr.jar in plugins: null
org.bukkit.plugin.InvalidPluginException
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:85)
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:129)
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:94)
    at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:58)
    at net.minecraft.server.MinecraftServer.e(MinecraftServer.java:187)
    at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:174)
    at net.minecraft.server.MinecraftServer.d(MinecraftServer.java:120)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:227)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:366)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:80)
    ... 8 more
Caused by: java.lang.NullPointerException
    at IcySeal.Tunnelr.TunnelrPlListener.<init>(TunnelrPlListener.java:18)
    at IcySeal.Tunnelr.Tunnelr.<init>(Tunnelr.java:25)
    ... 13 more
2011-02-27 15:43:53

I do believe this is caused by my YAML file though I do not see a problem.

Code:

name: Tunnelr
version: 1.0
main: IcySeal.Tunnelr.Tunnelr
commands:
  tunnelr:
    description:
    usage:

Edit: Nvm it was a world issue.

 

What did you fix? I have the same error but I'm pretty clueless.