NullPointerException when plugin is disabled

I am getting a bizarre NullPointerException on my plugin NoSpeedKick when I disable it. Here's the log:

Code:

2011-10-13 22:09:08 [INFO] NoSpeedKick 0.3 disabled
2011-10-13 22:09:08 [SEVERE] Error occurred (in the plugin loader) while disabling NoSpeedKick v0.3 (Is it up to date?): null
java.lang.NullPointerException
    at java.lang.Class.isAssignableFrom(Native Method)
    at org.bukkit.plugin.java.JavaPluginLoader.removeClass(JavaPluginLoader.java:245)
    at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:992)
    at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:296)
    at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:289)
    at org.bukkit.craftbukkit.CraftServer.disablePlugins(CraftServer.java:166)
    at net.minecraft.server.MinecraftServer.stop(MinecraftServer.java:325)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:404)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)
2011-10-13 22:09:08 [INFO] Saving chunks
2011-10-13 22:09:08 [INFO] Stopping server

I have no idea where this is coming from, so I'll just give my entire plugin source: <Edit by Moderator: Redacted mediafire url>

Any ideas on the cause of this? Thanks!!

 

The latest CraftBukkit seems to do this. The previous RB (1240) doesn't.

Not sure what changed or if something needs to be added to the onDisable method from here on.

 

That's a bug in 1317, fixed in 1318.
I still have no idea why they haven't changed the RB as every plugin I use does this error.