tl;dr I think it works now.

Current build is v0.3, which is up on the main server.
Fixed an error that will hopefully resolve the problems people have been having. Has fewer messages to the client, but mainly when something has gone wrong, messages are also more informative.
Flashy effect when you make exp bottles.
More detailed logs.

A summary on how to use it: Have xp, have empty glass bottles in your hand.
Right click on an enchanting table.
For every 25 xp (5 hostile mobs worth of xp) and 1 glass bottle in your hand you get 1 bottle o' enchanting.
If you have no room in your inventory, any remaining glass bottles in your hand are replaced with the exp bottles. When you throw the bottle o' enchanting you get back 25 xp.
You have to wait 30 seconds from when you log on and between making bottles to make more.

I would also like to reiterate the importance of reporting any bugs or errors you find on the github issues page.
More details is (almost) always better!

Edit: some people are still running into an issue that is preventing them from using the plugin, an explanation:
Bukkit stores the xp of players in 3 separate values: The number of levels, the progress to the next level and the total xp.
The third number can be calculated from the first two and the first two can be calculated from the third one.
Sometimes, for reasons I have been unable to figure out, the total exp value reported by bukkit is incorrect and not just incorrect but waaaay bigger than it should be, often an order of magnitude or 3 bigger than the correct number.
This is what the 'invalid xp values' error message refers to.