Where are the trader trolls

[asteriakingdom]

Hi,
I keep getting a pop up saying that I can trade monster loot with trader trolls but when I click 'go' at the bottom of the pop up it doesn't do anything. I can't find the trolls anywhere. Where do I find them and how do I trade with them?

[meme1098]

Here's the current goal related to that:

http://forums.storm8.com/showthread.php?83253-Castle-Story-07-16-Update-Monster-Hunt