Bukkit

What steps will reproduce the problem?
1. Install the plugin.
2. Add some achievements.
3. Type /ach

What is the expected output? What do you see instead?
I expect a list of achievements, but I get an internal error with an error in the console.

What version of Achievements are you using?
2.0.0

What version of Stats are you using?
2.0.1

Do you have an error log of what happened? If so, please provide it here using a pasting service.
http://pastebin.com/iqiaha7F

Please provide any additional information below.
There are no errors when I start the server (very recent Spigot 1.8 build). There is an another error caused by the same problem: http://dev.bukkit.org/bukkit-plugins/lolmewnachievements/tickets/26-cant-use-achievement-string-in-achievement-broadcast/

Ah yes. This is caused by spigot moving their included libs around. It has been fixed but the build in which it is fixed is not stable enough yet to be used.

Do you already know when the build can be released?

Fixing up Stats first. Basically, the new build itself works fine, it's just that the old version of achievements.yml is no longer valid and there's no converter for it yet.