I had noticed. Was driving me and my server users crazy also. Took me a while to track down so thought I could save you the trouble. :) ~Domesis
Is Craftbook Alpha 2 another of the plugins you are using? This has been a common error in the Craftbook thread, fixes are in the following link...
Sol over on the Minecraft forums has tried to get something like this going. Hasn't really taken off though....
Separate names with a comma.