Bukkit

What steps will reproduce the problem?
1.When a Player logs in, The player keep getting kicked for Moving too fast.
2.With Spoutcaft, It keeps encounters a problem and disconnect us from server.
3.Before Logging in, Players keep Shaking up and down very fast (Kicking for Flying is not enabled on this server)

What is the expected output? What do you see instead?
Before the 1337 update, It was working fine, Now it's really annoying.

What version of the product are you using?

Do you have an error log of what happened?(Server console output)

Please provide any additional information below.(config.yml)