bug

I have a 1.6.1 Bukkit server, and the once the console loads the server, it spams:

"[SEVERE] Reached end of stream for /xx.xxx.xx.xxx." And "/xx.xxx.xx.xxx lost connection" when no one is in game.

This only happens when I click in the "multiplayer" button to check if the server is online. Every time I do that, the server gives the [SEVERE] message.

I don't know what is going on, but it doesn't seem to affect players logging into the server. I'm using a 1.6.1 Bukkit Dev build, so that could be the problem. I do know that 1.5.2 never had that problem.