Bukkit

What steps will reproduce the problem?
1. Creating a server store of any item.
2. Trying to left click the sign.
3. Server error is created.

What is the expected output? What do you see instead?

I expect to be able to purchase from the server. Instead either nothing happens or it says I have no money. And I am running vault as well as only using one economy.

What version of the product are you using?

v1.46S

Do you have an error log of what happened?

[SEVERE] Could not pass event PlayerInteractEvent to DynamicShop
org.bukkit.event.EventException
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:304)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:460)
    at org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:177)
    at net.minecraft.server.ItemInWorldManager.dig(ItemInWorldManager.java:94)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:537)
    at net.minecraft.server.Packet14BlockDig.handle(SourceFile:43)
    at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
    at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:567)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:459)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
    at me.zylinder.dynamicshop.PlayerHandler.checkInventory(PlayerHandler.java:137)
    at me.zylinder.dynamicshop.TransactionHandler.buyGlobal(TransactionHandler.java:85)
    at me.zylinder.dynamicshop.SignHandler.leftClickGlobal(SignHandler.java:186)
    at me.zylinder.dynamicshop.DynamicShopPlayerListener.onPlayerInteract(DynamicShopPlayerListener.java:59)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302)
    ... 12 more

Please provide any additional information below.

The only economic plugins I am using are: iConomy and DynamicShop. Also Vault is installed and I have the latest version.