The pastebin for the error: http://pastebin.com/kXrHdKHQ
Looks like your plugin is trying to use a class that doesn’t exist (org/spongepowered/api/service/ProviderExistsException).
Have you tried installing another plugin?
This looks like you’re using a plugin that hasn’t been updated to the latest version of Sponge. Make sure you’ve updated all of your plugins.
Try updating your Sponge Version too, you’re running a fairly old build.