Bukkit

What steps will reproduce the problem?
1. Open a server side shop
2. Set a cooldown on an item - 10 items, 1 day limits; either buying or selling
3. Purchase or sell items without limits. Exception in console is noticed.

What is the expected output? What do you see instead?
I expect the buyer to not purchase more than 10 items, or the seller to not sell me more than 10 items. Instead I have unlimited buying and selling.

What version of the product are you using?
2.1.2

Do you have an error log of what happened?
I have the console output, here's the pastebin http://pastebin.com/cPxeLpmp

Please provide any additional information below.