Bukkit

What steps will reproduce the problem?
1. /buy stone 1
2. /sell stone 1
3.

What is the expected output? What do you see instead?
An internal error occurred while attempting to perform this command.

What version of the product are you using?
I've tried every version up to the last. I've also tried removing every other pluggin.
I have tried many versions of iconomy, currently using the latest iC6

Do you have an error log of what happened?

org.bukkit.command.CommandException: Unhandled exception executing command 'buy' in plugin DynaMark v0.1.0.0
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:165)
    at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:378)
    at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:757)
    at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:722)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:715)
    at net.minecraft.server.Packet3Chat.a(Packet3Chat.java:33)
    at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:93)
    at net.minecraft.server.NetworkListenThread.a(SourceFile:108)
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:527)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
Caused by: java.lang.NoClassDefFoundError: net/milkbowl/vault/economy/Economy
    at me.smickles.DynamicMarket.DynamicMarket.buy(DynamicMarket.java:482)
    at me.smickles.DynamicMarket.DynamicMarket.readCommand(DynamicMarket.java:252)
    at me.smickles.DynamicMarket.DynamicMarket.onCommand(DynamicMarket.java:237)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
    ... 12 more
Caused by: java.lang.ClassNotFoundException: net.milkbowl.vault.economy.Economy
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:36)
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:24)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    ... 16 more

Please provide any additional information below.

Thanks for your help.

Hmm, DynaMark should work with iC6... Do you have Vault in your plugin folder as well? DynaMark needs vault there in order to interact with economy plugins.