Villagers offer Enchanted Book trades you can't possibly do

Can you attach a world with one of these trades?

Added the file. Note that I deleted all the unrelated chunks to reduce file size, coords of the villager are x: 7147, y: 38, z: -4835

Here's a screenshot of the trading gui.

adding link cause I couldn't get the attact screenshot to work.
https://dl.dropbox.com/u/18835236/Games/Minecraft/issues/javaw%202012-12-28%2023-46-51-76.png

off-topic.. that's a nice way of transporting items, the water/ice pathway

How did you get the colored signs? That seems to point to a non-vanilla world.

Yes, the villager / world in question is from a bukkit server with some plugins, but none of which affect the villager trading calculations. As I'd rather not spend another 10+ hours of trying to get lucky, especially since someone has already dug into the code on how the trade costs are calculated. ( http://www.minecraftwiki.net/wiki/Talk:Trading#Enchanted_Books )

Edit: Though if someone else wants to get another occurrence of this, be my guest.

This could be resolved if Block of Emerald counted as 9 Emerald for the purpose of trading and they left your change in the GUI.

Why not just cap the maximum number of emeralds needed for level V enchanted books to 64.

That would be a very very simple fix!

Has this been fixed due to the recent changes to Villager trading?

Yes, it appears the new trading properly caps the maximum amount of emeralds at 64.

Why not allow villagers to have a trade quota, you can give them a "Pay" button so the number of emeralds will go down with each pay. That way you can pay in multiple stacks if one of the slots must be occupied as well. It will only get the required items using Pay buttons. This idea resolves most of the trading problems.