Bukkit

What version of DynamicEconomy are you using?:

v.9.2

Try to explain how to arrive at the problem:

1) I'm using the YAPP permission plugin, I put in all the permissions correctly, rechecked
them too. For some reason when I go to test out some of the commands like /buy,
it says "Internal Error" in chat.

Please paste the error log, if any. (Also provide DynamicEconomy log)

Server.log

2013-01-19 10:37:24 [INFO] Aycardus issued server command: /price
2013-01-19 10:37:28 [INFO] Aycardus issued server command: /price wood
2013-01-19 10:37:40 [INFO] Aycardus issued server command: /buy wood 10
2013-01-19 10:37:40 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'buy' in plugin DynamicEconomy v.9.2
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
    at org.bukkit.craftbukkit.v1_4_6.CraftServer.dispatchCommand(CraftServer.java:510)
    at net.minecraft.server.v1_4_6.PlayerConnection.handleCommand(PlayerConnection.java:980)
    at net.minecraft.server.v1_4_6.PlayerConnection.chat(PlayerConnection.java:898)
    at net.minecraft.server.v1_4_6.PlayerConnection.a(PlayerConnection.java:853)
    at net.minecraft.server.v1_4_6.Packet3Chat.handle(Packet3Chat.java:44)
    at net.minecraft.server.v1_4_6.NetworkManager.b(NetworkManager.java:290)
    at net.minecraft.server.v1_4_6.PlayerConnection.d(PlayerConnection.java:112)
    at net.minecraft.server.v1_4_6.ServerConnection.b(SourceFile:39)
    at net.minecraft.server.v1_4_6.DedicatedServerConnection.b(SourceFile:30)
    at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:598)
    at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
    at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)
    at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)
    at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
    at me.ksafin.DynamicEconomy.Transaction.buy(Transaction.java:231)
    at me.ksafin.DynamicEconomy.DynamicEconomyCommandExecutor.onCommand(DynamicEconomyCommandExecutor.java:256)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
    ... 15 more

DynamicEconomy Log

+ [2013-01-19 10:37:18.234] Aycardus logged in.
+ [2013-01-19 10:37:24.471] Aycardus incorrectly called /price
+ [2013-01-19 10:37:28.656] Aycardus called /price for item WOOD
+ [2013-01-19 10:37:46.555] Aycardus incorrectly called /buy

Thanks in advance!

This is also occurring when I try to sell something.

Here's the plugins I'm using:

SimpleBackup,WorldEdit, NoCheatPlus, CommandBook, OpenInv, Vault, ProtocolLib, CombatTag, mcMMO, WorldGuard, Factions, SilkSpawners, YAPP, MagicSpells, Disguisecraft, DynamicEconomy, VanishNoPacket, Enjin Minecraft Plugin.