Is there a way to fix it?

2012-04-21 15:50:05 [SEVERE] Error occurred while enabling Vault v1.2.15-b172 (Is it up to date?)
java.lang.NoClassDefFoundError: com/palmergames/bukkit/towny/NotRegisteredException
at net.milkbowl.vault.Vault.loadChat(Vault.java:214)
at net.milkbowl.vault.Vault.onEnable(Vault.java:109)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:215)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:336)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:383)
at org.bukkit.craftbukkit.CraftServer.loadPlugin(CraftServer.java:355)
at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:337)
at org.bukkit.craftbukkit.CraftServer.(CraftServer.java:285)
at net.minecraft.server.ServerConfigurationManager.(ServerConfigurationManager.java:53)
at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:188)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:475)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.ClassNotFoundException: com.palmergames.bukkit.towny.NotRegisteredException
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.findClass(PluginClassLoader.java:41)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:29)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 12 more

I don't support development versions, I'll get it patched though.

fixed in last commit.

Where can i find the fix, i dont know what a commit is.
Are there dev builds for vault ?

sorry, http://ci.milkbowl.net