This is 6.4.1_dev, Fix Vault NPE.

plugin.yml

@@ -1,6 +1,6 @@
 main: com.massivecraft.mcore.MCore
 name: mcore
-version: 6.4.0
+version: 6.4.1_dev
 website: http://massivecraft.com/mcore
 authors: [Cayorion]
 description: §eMCore stands for MassiveCraft Core and is a plugin that contains libraries and features that other plugins make use of. §aCayorion §efrom the minecraft server §aMassiveCraft §eis the lead programmer. Feel free to visit us at §bhttp://massivecraft.com

src/com/massivecraft/mcore/money/MoneyMixinVault.java

@@ -25,6 +25,7 @@ public class MoneyMixinVault extends MoneyMixinAbstract
 	public void activate()
 	{
 		RegisteredServiceProvider<Economy> rsp = Bukkit.getServicesManager().getRegistration(Economy.class);
+		if (rsp == null) return;
 		this.economy = rsp.getProvider();
 		Money.mixin(this);
 	}